Yes, that's listed on the wiki page.
CPC == 3 levels of RGB (3**3 == 27 colors), 16 or 4 or 2 onscreen (according to screen mode)
EGA16 == 2 levels of RGB (off/on), plus one intensity bit which adds 7f7f7f to the color == 16 colors, of which 16 can be displayed onscreen
(not necessarily in the same order or quantity. palette cycling and fading was possible)
EGA64 == 4 levels of RGB (4**3 == 64 colors), 16 onscreen normally.
Genesis / Megadrive == 8 levels of RGB (8**3 == 512 colors), max 62 onscreen [1]
Amiga ECS == 16 levels of RGB (16**3 == 4096 colors), 2/4/8/16/32, or 64 [2]
CPC+ == 16 levels of RGB (16**3 == 4096 colors), 16/4/2 onscreen (more possible, using hardware sprites); Slightly different from Amiga ECS master palette in that the green channel uses a mildly altered intensity curve vs the blue and red channels.
SNES == 32 levels of RGB (32**3 == 32768 colors), 256 colors / scanline plus simple hardware compositing [3]
MCGA / VGA == 64 levels of RGB (64**3 == 262144 colors), 256 or 16 onscreen
Amiga AGA == 256 levels of RGB, 2/4/8/16/32/64/128/256 colors onscreen.
Onscreen color limits are per-scanline. Which doesn't necessarily mean that you could change the palette every scanline to vastly increase the total amount of displayed colors. Usually you could manage to change the palette at least twice per refresh, though.
Some games (like Switchblade on the CPC) implemented vertical text gradients by changing one palette entry every scanline.
On some systems, like PC's, this trick is very difficult to do reliably because there is no fixed hardware.
Most color systems described here tend to have a direct relation to standard sRGB. I think CPC has slightly different intensity curve than sRGB, though.
My software 'PixLab' supports quantizing accurately to these colorspaces, and I can easily provide lookup-tables for this (it's surprisingly tricky to do correctly). I could provide palettes, however: 4096-entry palettes? not practical. IMO 256 is about the limit of managability, like happymonster says.
[1] two 16-color palettes for background tiles, and 2 15-color palettes for sprites ( the 16th entry represents transparency)
[2] any hex color #RGB is a color from the Amiga master palette, and any hex color #RRGGBB where the two R,G,B digits match.
64-color mode was EHB 'extra half-brite' mode, where you could not choose the extra colors, the extra bitplane just specified 'halve the intensity of the color of this pixel' where a bit was set. If you pick a 32-color palette, then copy it and apply Levels 0..128 to the copy, you
will have a result that may be right (documentation on this is not clear; it just says 'halve intensity' -- is the resultant intensity quantized to the 16**3 limits of Amiga OCS or not?)
Details about HAM modes intentionally omitted.
[3] any hex color #RRGGBB where the second R,G,B digits are one of (0,8) is a color from the SNES master palette.
This means that #f8f8f8 is the closest to white you can come.
EDIT: Updated according to saimo's post about AGA and my info about Genesis, SNES.
EDIT2: Updated according to saimo's later post.
EDIT3: added CPC+ info