One idea I've had with regards to picking Pokemon is looking at Ash's Pokemon and the Pokemon of all his Companions. If that doesn't add up to 64, then you add in rivals such as Paul, Trip and Gary(Gary's Umbreon would be sick, although Gladion's....). Then to determine winners you use a six sided die and roll as many times as needed to score three hits. If there are no advantages or each Pokemon has a Type Advantage over the other(like Brock's Steelix vs. Kiawe's Turtonator), then each Pokemon gets an equal amount of numbers on the die. If one Pokemon has the advantage, then they get 4 numbers as opposed to just three. You then roll until one Pokemon acquired 3 successful hits(a hit being that their number rolls up). In other words, it's best of five or first to three wins. I mean you could do a popularity contest to determine winners(which would be an outright headache to carry out or determine a winner) or simply have people try and guess the outcome before rolling.
Another idea is to do Attack&Save(aka Great Pokemon Battle) for each matchup(you know... the popular game here on the Forum). Should a Pokemon faint, it loses and the winner moves on. Conversely if a Pokemon hits 60 through being saved, it automatically wins. Think of it like a Pokemon Contest Battle where fainting the Pokemon isn't the key to victory. Type advantage would have double the effect for an Attack to help speed things up.
Oh and one more thing. I'm tempted to start one while giving you credit for the inspiration.