Cards like Unruly Catapult, Galvanic Juggernaut, Traxos, Scourge of Kroog, Staff of Compleation, Bender's Waterskin, and the game changer, Mana Vault all have ways to untap themselves
#2 One of the first decks I made, after getting into commander, was The Briny Deep
Start with at least 10 counterspells as the number of counterspells you should play in Commander, and it really depends on the deck youre building
The archetype certainly can be tuned to high-power tables, though play a high density of lifegain cards and creature tutors, and play your game aiming for a combo finish
On MTG: Arena if you crafted a copy for a prior set, you can use that card again if it re-enters Standard
The focus is on aggressive creatures and burn spells, with little room for red card draw