https://www.sendspace.com/file/xcfioi

Here are a few so far; more for people interested in this topic to download them if they wish; than to suggest them, although they are each quite good!

These are not on J2O, but may indeed be somewhere on J2C!

Funky Trousers, by Gizmo, Battle
Dino Dynamics, by Dino, CtF
Loon Lagoon, by (not sure!), Battle (uniquely large and spread out for Battle, but very coherent and fun level design!)

One more is on J2O; I thought at first that it is by MErlin, but I couldn't remember whether or not MErlin actually made levels, so this may be someone with a similar name: Merlyn
Rockingham Gardens, Battle