Notes & Combos
For a Ritual deck, Drytron sure Xyz summons a lot. The first thing you're searching with Thuban is always Batosbuster, who you'll summon using 1 mat from Mu Beta to search Unlocking. Just this at minimum is 2 Spell/Trap negates. From here, it depends what your hand looks like. If you can get Draconids in rotation, that's a double pop on top of your 2 negates, or if you can get a couple more level 1's out, you can trade in your Mu Beta for UDF.
Only important Xyz are Mu Beta and the UDF/Zeus packages. Everything else is just filler Rank 1's or Seven Sins since you can make it in theory.