A friend of mine is running a one shot and invited me join in. The group with be made up of 7 PCs and we will all be lvl 20. Most magic weapons are up for grabs and no restrictions on class or race. I work better with boundaries so this is a bit overwhelming lol.

I need some help! Would appreciate anyone’s thoughts or input on a fun lvl 20 build.

How about a level 20 Arcana Domain Cleric?  Reasons why:

• Channel Divinity: Arcane Abjuration hits celestials, elementals, feys, and fiends.  At level 20 you may run into a lot of these type of creatures.
• Spell Breaker can remove debilitating spells on your allies.  Again, at level 20, you may face a lot of these type of spells.
• Arcane Mastery steals 4 high level wizard spells.  A great selection of spells here.
• Divine Intervention at level 20 automatically succeeds.

Get wisdom to 20, dexterity to 14, use a shield, and wear medium armor.  And have fun!

Thank you! This build seems pretty solid. 

ok, so it really is up to what you want to play but I would advise the following.

• don't multiclass whether your DM allows it or not (20th level abilities are much better than two tenth level ones)
• pick race after class (this allows you to optimise your character)
• any class will be fine unless more than 2 of you want to play the same class (maybe check what other players are playing)
• choose at least 1 feat they make any level character so much more fun to play (only if your DM allows it)
• bear in mind that the difference between a +3 modifier and a +4 modifier at 20th level is 20hp
• if you want something game-changing choose a class that knows the wish spell
• this is also a good opportunity to get a feel for a class you haven't played before

but most of all make a character that you will enjoy playing, hope this helps.

Thank you Oozy! This definitely helps. I appreciate you taking the time to share.