Ivy, Gleeful Spellthief makes it so whenever a player casts a spell that targets only a single creature other than her, you can immediately copy it and target Ivy herself
Theyre legal to play but exist purely as collector trophies
Taeko, the Patient Avalanche This four-mana mono-Blue 4/5 Turtle Ninja ETBs tapped, and then when another dork you control leaves without dying, you can scry 1 and toss a +1/+1 counter here
Just be sure to protect those Forces in style with custom deck boxes
Glissa Sunslayer can remove lore counters from any saga
Ive been playing a lot of Standard on Arena recently (and pretty well, if I do say so myself), and while the decks I wrote about above are the core of the format, theres still room for surpise