The burn damage Descent into Avernus does can become big in the later stages of the game if you cast it early
Theres a firm argument for only printing proxies with official art so theres zero mix ups, but custom art works so long as all players can tell what the card does
Kaalia of the Vast is unique in that it rewards playing with 3 tribes instead of just 1, and gives you a way to play the traditionally big, expensive Demons, Dragons, & Angels from your hand simply for attacking
There are 15 in total: Onix Sudowoodo Gligar Gliscor Swinub Piloswine Mamoswine Phanpy Donphan ex Tyrogue Hitmontop Larvitar Pupitar Binacle Barbaracle These are all the Dark-type Pokmon cards in Wisdom of Sea and Sky
If you can bounce one of their spells during their turn in which they cant recast it that turn, you could then play Comply during your turn to make sure they cant cast it during their next turn
Cards like Neo Upper Energy will help accelerate your primary attackers when conditions are met and can put you leagues ahead of your opponent