I have a few suggestions for the modpack, and the testing server.
JourneyMap - Quality of life, all survival modpacks need a minimap!
Morpheus - Quality of life, sleep voting.
An Essentials plugin - Quality of life, homes.
FastLeafDecay - This increases the tick rate on decaying leaves, quality of life, but also will be interesting to see how this works with a sponge server.
Psi - This is just a fun mod I want.
Dynamic Surroundings - I just really love this.