You want to create game graphics for some kind of retro style game but don't know which colors to use?
Here's a small selection of color palettes I found in the web which you can export to GIMP palette or AdobeSwatchExchange file.

Current number of palettes: 133

Open Color Palette

132 colors

Palette for color blind people taken from https://yeun.github.io/open-color

3DTin

72 colors

http://www.3dtin.com/

Adobe SketchBook

30 colors

https://play.google.com/store/apps/details?id=com.adsk.sketchbook

Amiga

31 colors

Amiga generic palette

Amstrad CPC

27 colors

n.a.

Android icon palette

15 colors

https://bugs.launchpad.net/inkscape/+bug/602698

Android ICS

10 colors

https://developer.android.com/design/style/color.html

AndroidArts

16 colors

n.a.

Apple II

15 colors

n.a.

Arne CNES 88

64 colors

n.a.

Arne Palette V2.0

17 colors

n.a.

arq4

4 colors

Colors by ENDESGA via https://forums.tigsource.com/index.php?topic=46126.msg1335540#msg1335540

Atari2600

103 colors

n.a.

Atari 2600 NTSC

127 colors

n.a.

Atari 2600 PAL

104 colors

n.a.

Bamboo Paper (by Wacom)

37 colors

Bamboo Paper (Android app by Wacom)
http://bamboopaper.wacom.com/
https://play.google.com/store/apps/details?id=com.wacom.bamboopapertab

Breeze

33 colors

https://techbase.kde.org/Projects/Usability/HIG/Color

Breeze (Extended)

41 colors

https://techbase.kde.org/Projects/Usability/HIG/MockupToolkit

C64-pepto-sorted

16 colors

n.a.

C64-c128

16 colors

n.a.

C64-c64s

16 colors

n.a.

C64-ccs64

16 colors

n.a.

C64-deekay

16 colors

n.a.

C64 dirty

16 colors

n.a.

C64-frodo

16 colors

n.a.

C64-gryf_elysium

16 colors

n.a.

C64-jpz

16 colors

n.a.

C64 light

16 colors

n.a.

C64-moog_agony

16 colors

n.a.

C64 old

16 colors

n.a.

C64 old2

16 colors

n.a.

C64-pepto

16 colors

n.a.

C64-vice

16 colors

n.a.

C64-wanja

16 colors

n.a.

C64-wanja_inverse

16 colors

n.a.

CGA Full Palette

16 colors

n.a.

Colorize - complete

146 colors

Palette for coloring black and white images with the GIMP ColorizePlugin

Colorize - fabric jeans

9 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Colorize - fabric misc

24 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Colorize - human eyes

17 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Colorize - human hair

12 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

colorize_human_lips

8 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Colorize - human skin

14 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Colorize - nature flowers

8 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Colorize - nature grass

13 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Colorize - nature stones

18 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Colorize - nature water

10 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Colorize - nature wood

13 colors

Palette zum Einfaerben von S/W-Bildern mit dem ColorizePlugin.

Commodore Plus4

117 colors

7

Commodore VIC-20

16 colors

n.a.

Crayola V. 1.1

116 colors

http://rosros-3.deviantart.com/art/Crayola-368592163
https://en.wikipedia.org/wiki/List_of_Crayola_crayon_colors

CrayolaByHue V. 1.1

116 colors

http://rosros-3.deviantart.com/art/Crayola-368592163
https://en.wikipedia.org/wiki/List_of_Crayola_crayon_colors

CSS Color Module Level 4 named colors

139 colors

http://dev.w3.org/csswg/css-color/#named-colors

DawnBringer

16 colors

n.a.

db32.gpl

32 colors

n.a.

Doodle or Die

16 colors

http://doodleordie.com/

Draw My Thing (OMGPOP)

13 colors

n.a.

Draw Something (by OMGPOP)

124 colors

Draw Something (mobile game by OMGPOP)
https://play.google.com/store/apps/details?id=com.omgpop.dstfree
https://play.google.com/store/apps/details?id=com.omgpop.dstpaid

draw.io

142 colors

https://www.draw.io/

Drawception Halloween

17 colors

n.a.

Drawception Holiday

8 colors

n.a.

Drawception Neon

7 colors

n.a.

Drawception Spring

11 colors

n.a.

Drawception Thanksgiving

9 colors

n.a.

Drawception The Blues

9 colors

n.a.

Drawception Valentine's

10 colors

n.a.

edg16

16 colors

By ENDESGA Studios
https://twitter.com/ENDESGA

edg32

32 colors

By ENDESGA Studios
https://twitter.com/ENDESGA

edg8

8 colors

Colors by ENDESGA via https://forums.tigsource.com/index.php?topic=46126.msg1335540#msg1335540

EGA Full Palette

64 colors

n.a.

en4

4 colors

Colors by ENDESGA via https://forums.tigsource.com/index.php?topic=46126.msg1335540#msg1335540

enos16

17 colors

Colors by ENDESGA via https://forums.tigsource.com/index.php?topic=46126.msg1335540#msg1335540

Famicom

54 colors

n.a.

Flourescent Swatches

92 colors

n.a.

Forest palette - dark

63 colors

Created by Arachne - CC-BY-NC-SA

Forest palette - fall

64 colors

Created by Arachne - CC-BY-NC-SA

Forest palette - frost

63 colors

Created by Arachne - CC-BY-NC-SA

Forest palette - rainy

62 colors

Created by Arachne - CC-BY-NC-SA

Forest palette - snow

56 colors

Created by Arachne - CC-BY-NC-SA

Forest palette - sunny

69 colors

Created by Arachne - CC-BY-NC-SA

GameBoy

4 colors

n.a.

GameboyColor

32 colors

n.a.

Gmail label colors

64 colors

Colors from Gmail labels.

GNOME Human Interface Guidelines

32 colors

https://developer.gnome.org/hig-book/stable/design-color.html.en#Palette

Google Drive

80 colors

Colors from Google Documents and Google Sheets

Google Hangouts Sketch a message

32 colors

https://www.yahoo.com/tech/you-can-now-draw-messages-for-your-friends-in-google-88695389164.html

Google Keep - drawing

28 colors

Colors for drawing inside Google Keep.
https://play.google.com/store/apps/details?id=com.google.android.keep

Google Keep - notes

8 colors

Note colors from Google Keep.
https://keep.google.com/

Grafxkid's 20P DX

20 colors

n.a.

Grafxkid's 24P DX

24 colors

n.a.

Grafxkid's 29P DX

29 colors

n.a.

Grafxkid's 30 Color V1.0

30 colors

Date: 2014-04-01

Grafxkid's 46 Color

47 colors

n.a.

Grafxkid's LCPB

31 colors

n.a.

HW 6-bit RGB (EGA and Sega Master System)

64 colors

https://en.wikipedia.org/wiki/List_of_monochrome_and_RGB_palettes#6-bit_RGB
https://en.wikipedia.org/wiki/Enhanced_Graphics_Adapter#Color_palette
http://segaretro.org/Palette
python3 -c 'l=[0,85,170,255]; [print(a,b,c) for a in l for b in l for c in l]'

HW Atari 2600 (SECAM)

8 colors

https://en.wikipedia.org/wiki/List_of_video_game_console_palettes#Atari_2600

HW CGA (4-color modes)

14 colors

https://en.wikipedia.org/wiki/List_of_8-bit_computer_hardware_palettes#CGA

HW CGA (earlier CRTs)

15 colors

https://en.wikipedia.org/wiki/List_of_8-bit_computer_hardware_palettes#CGA

HW Commodore 16 and Plus/4

121 colors

https://en.wikipedia.org/wiki/List_of_8-bit_computer_hardware_palettes#C-16_and_Plus.2F4

HW Commodore Plus/4 default palette

12 colors

https://en.wikipedia.org/wiki/List_of_8-bit_computer_hardware_palettes#C-16_and_Plus.2F4

HW Kleincomputer KC 85

21 colors

https://de.wikipedia.org/wiki/Kleincomputer_KC_85/2-4
https://en.wikipedia.org/wiki/Robotron_KC_85
http://www.robotrontechnik.de/html/forum/thwb/showtopic.php?threadid=1430

INKredible

33 colors

http://inkredibleapp.com/
https://play.google.com/store/apps/details?id=com.viettran.INKredible
https://itunes.apple.com/us/app/inkredible/id712303681

kaiseto

72 colors

Taken from Pixeljoint forums

MasterSystem

31 colors

n.a.

Mattel Aquarius

16 colors

n.a.

MegaDrive

60 colors

n.a.

Mindly

28 colors

Mindly mobile app
http://www.mindlyapp.com/
https://play.google.com/store/apps/details?id=com.dripgrind.mindly
https://itunes.apple.com/us/app/mindly/id771221376

MindMup

36 colors

Node colors from MindMup.
https://www.mindmup.com/

MSX

15 colors

n.a.

NES

55 colors

n.a.

pico-8

16 colors

Taken from www.pico-8.com / CC-0

Pixelator.co

24 colors

http://www.pixelator.co/
https://github.com/clarkduvall/pixelator

pixpix32

32 colors

Created by Henri Rochefort (@pixhammer)
for Aseprite 1.2+
https://pixhammer.itch.io/pixpix32

Qrauler

13 colors

Created by @EnchaeC (Twitter)

Realtimeboard

24 colors

https://realtimeboard.com/

Sega Master System

32 colors

n.a.

Skedio

20 colors

http://skedio.shturmsoft.com/
https://play.google.com/store/apps/details?id=com.shturmsoft.skedio

Sketch Toy

18 colors

http://sketchtoy.com/

skintones

60 colors

Extracted from different face pixel graphics

Symphonical

24 colors

https://www.symphonical.com/

Teletext

8 colors

n.a.

Thomson MO5

16 colors

n.a.

Grafxkid's TodayLandPalette

32 colors

n.a.

Trello labels

11 colors

Label colors from Trello

VoxelShop (by BlackFlux Software)

49 colors

https://blackflux.com/node/11

Wads Optimum 16 Color Palette

16 colors

n.a.

we draw comics

30 colors

Palettes from http://beta.wedrawcomics.com/
Each comic has 10 colors (5 grayscale + 5 custom colors).

Windows 16 Color Palette

15 colors

n.a.

Windows 7 MS Paint

20 colors

n.a.

Windows XP MS Paint

28 colors

n.a.

Write (Stylus Labs)

29 colors

n.a.

X-Flourescent Swatches

54 colors

n.a.

ZX Spectrum

15 colors

n.a.