There are a few legendary ooze creatures that can be your commander
The classic internet wisdom here is that Averna is theoretically less scary than other cascade commanders and less likely to get sniped by opponents, but I tend to use my removal on rampy commanders early if I can, and anyone whos played the deck knows that's a good idea
These items are still exceedingly rare to find in mainline games, which makes sense, as theyre used for increasing your Pokmons stats
Mana ramp involves finding ways to get more of your lands onto the battlefield as quickly as possible and/or creating reusable sources of mana through permanents on the battlefield
You should bring a tournament-legal Deck as described above, along with any tournament supplies you will need, such as paper and pen to track Life Points, dice or counters if you are using cards which require them, extra sleeves to replace any that become damaged, and so forth