SkyWars by CookLoco
$13, unfortunately the last update was 1.12. Try a free one beforehand.
https://www.spigotmc.org/resources/skywars-uuid-support-new-features-and-many-bug-fixes.6525/
SkyWars Reloaded
Free, but again this time it's still not being updated. It's 1.13 this time though. As it's free I would try this first.
https://www.spigotmc.org/resources/skywarsreloaded.3796/
UhcPlugin by PauMAVA
Free, and is tested on 1.15! It comes with a lot.
https://www.spigotmc.org/resources/uhcplugin.70665/
UHC Pie by Me
Well, it's not a plugin, but it's a script! WIP and half-manual, so I have literally no idea why I put this here.
Reasons why I want new plugins
UHC-Core is good, but every server has it. There's no variety. Every time you join a UHC server, it's the same thing. I would say this about ScreamingBedWars but the thing about that is the fact there are maps. In UHC-Core it's the same thing most of the time. For SkyWars, well, it just doesn't work.