This modpack is perfect for PvPers. Mods such as small totem pops are great so you can see more when you're in battle! Also another good one is world host so you can host worlds to battle your friends, on top of that I have added in some QoL features as well. It includes ViaFabricPlus. If your looking to play a server for an older version then simply change the version using the button, then join it and boom! This modpack works with all versions! look at some more here. I made this pack because of my love to PvP. I hope the mods in here help you while in battle!
I would recommend PvP Legacy if you want the best 1.9 pvp experience.
I would highly recommend Hypixel if your looking for a 1.8 pvp server
As said above viafabricplus lets you join servers from any version. If theres a version you really really want for whatever reason fork the repo on GitHub and make it yourself!