Now that you know how to play, its finally time to start looking through your cards, build a deck with your favourite Pokmon, and start playing some games
Without Pidgeot ex around, the strongest search card is arguably Noctowl and its Jewel Seeker ability, one that fits well into just about any Tera Box deck
If Reveillarks in the graveyard, cast Karmic Guide targeting it, then respond by sacrificing Karmic Guide to Altar and mill and opponent for two cards
Legendary creatures have immensely powerful associated Commanders like Jodah the Unifier, and Sagas are finally picking up steam with back-to-back inclusions in Tales from Middle Earth, Wilds of Eldraine, and Universes Beyond: Doctor Who
You can also probably get away with just running one copy in the deck if you have a card you use to add a little utility or support to your strategy, or one that you use as your silver bullet against certain strategies that are more common in the metagame