Posting my (YR) custom maps from ages past here, per the advice of an upstanding member of this forum =p
Feel free to try, edit, or do whatever with them what you want. As said in my separate post, some of them might have overpowered spots etc, so it's probably worth taking a look at before using them in multiplayer (I didn't built them with pvp in mind methinks)
(Also they're in YRM/MPR format so probably need converting anyway)
4 isles.yrm
a visit to the park.yrm
base eraser.mpr
easy to get.yrm
grass city.yrm
icey.yrm
sand in your eyes.yrm
yuri's outhouse.yrm