Toon Kingdom
Not only is it a 4/5 attacker with flying, vigilance, and trample any time you want her to be, but if you want her to sit back you can turn a small creature into a threat each combat
PsyStall and DFW have both won tournaments in more recent history
Culmination of the Monarchs Continuous Trap Card Once per Chain, if your opponent Special Summons a monster(s) and you control a Tribute Summoned monster: You can banish 1 "Monarch" Spell/Trap from your GY, then activate 1 of these effects (but you can only use each effect of "Culmination of the Monarchs" once per turn)
Thanks to how many cards enable the strategy, there are many levels to play it, from low power to the highest levels
Only finding cards with flashback or disturb makes it fairly narrow, but I can see a casual deck built around flickering it as a draw engine to find cards like Mirrorhall Mimic and Deep Analysis