Because I'm bored, I'll do a list. Feel free to add to it with whatever I left out.

EPISODE 1: TURTLE TERROR
Diamondus
Conversions: A lot, and a pretty complete one by NOKA.

Tubelectric:
Conversions: Ones that come to mind are Newspaz's and NOKAs.

Medivo:
Conversions: Ones that come to mind are CelLs, which is pretty complete imo.

EPISODE 2: BALLISTIC BUNNY

Letni:
Conversions: One by I think CelL, which isn't so good. Needs a better conversion IMHO.

Technoir:
Conversions: Ones that come to mind are Newspaz's. Which is incomplete. Probably needs a better one.

Orbitus:
Conversions: Violet conquered this one.

EPISODE 3: MAKING PANCAKES WITH YOUR MOM RABBITS REVENGE

Fanolint:
Conversions: After a while of searching I found a useable one by IceWolf. Still incomplete, though.

Scraparap
Conversions: Two by Violet (one old one one new and better one)

Devan's Megairbase:
Conversion: A pretty good one by Violet.

EPISODE 4: GENE TOAST MACHINE

Turtemple
Conversions: NOKA. And some palette edits too.

Nippius
Conversions: One old but still good one by Violet.

Jungrock
Conversions: A moderately good one by CelL and a good one by LRK.

EPISODE 5: THE CHASE IS ON

Marbelara
Conversions: A good one by CelL comes to mind.

Slugion
Conversions: A pretty good (and really old) one by Violet.

Dreempipes
Conversions: Violet =D

EPISODE 6: THE FINAL CLASH

Pezrox: One by FoD (I think), and one by Violet.

Crysilis: One by someone (forgot who, USER INPUT PLZ). Needs a better one.

Twin Mega Battleships: Pretty good one by CelL the kangaroo

Time for the annoying episodes where I close the jj1 manual and actually use J1CS to check for =D

Exoticus
Conversions: Violet =D (with special appearance of POLAR BEAR)

Industrius
Conversions: Lots of people. One that comes to mind is LRK. Might or might not need another conversion.

Muckamok
Conversions: Lots, although most are fairly/moderately incomplete or fused with other conversions in a threesome or something. (NeW's Mayhem). Probably needs a good, solid conversion.

Raneforus
Conversions: Uh..the one that came with JCS. Thats it. And maybe some fused together/incomplete one which I can't recall atm. Needs a good conversion.

Stonar
Conversions: A few by CelL and one by LRK. Dunno if it needs another conversion or not, but LRKs was alright last I remembered.

Whatever this other planet is called (not paid to check in jj2 so dont care =D)
Uhh..Appears in NeW's Mayhem, and I think thats it. Needs a conversion.

Ceramicus
Conversions: Good one by NOKA.

Deserto (CLIFF IS COL. EAT ME! =D)
Conversions: Violet. gg

Lagunicus.
Conversions: Violet. gg
(On a side note, the boss level in lagunicus has a swear word written in it ;()

Candion
Conversions: A fairly good one by Violet (lacks some stuff, but oh well). Doesn't really need one at the moment.

Bloxonius
Conversions: An OK one by Toxic Bunny, some not so good random ones, a fairly good one by LRK.

Holidaeous (sp?)
Conversions: Violet. I think

I could post the descriptions for the episodes and stuff, but I don't feel like going through all the trouble to look up stuff for a post =D.