The first selection of Full Art Trainer Supporters featured a ridged border to the righthand side of the card that reminds me a bit of e-series Pokmon
Pauper & Peasant Cubes: Rarity-restricted cubes using only commons/uncommons, respectively
If I do this for every trigger, I could select the same targets 1000 times, and after the first resolves, the remaining items on the stack would just disappear because they no longer have legal targets

Foil-Only Future Sight Frame Cards 0243_MTGMB2_Fut_Foil: Foil 0244_MTGMB2_Fut_Foil: Urza, Lord High Artificer 0245_MTGMB2_Fut_Foil: Gix, Yawgmoth Praetor 0246_MTGMB2_Fut_Foil: Dragon's Approach 0247_MTGMB2_Fut_Foil: Squee, Goblin Nabob 0248_MTGMB2_Fut_Foil: Multani, Yavimaya's Avatar 0249_MTGMB2_Fut_Foil: Titania, Protector of Argoth 0250_MTGMB2_Fut_Foil: Captain Sisay 0251_MTGMB2_Fut_Foil: Gerrard, Weatherlight Hero 0252_MTGMB2_Fut_Foil: Mirri, Weatherlight Duelist 0253_MTGMB2_Fut_Foil: Xantcha, Sleeper Agent 0254_MTGMB2_Fut_Foil: Arcane Signet 0255_MTGMB2_Fut_Foil: Karn, Legacy Reforged 0256_MTGMB2_Fut_Foil: Command Tower 0257_MTGMB2_Fut_Foil: Reflecting Pool Playtest Cards Return First seen in Mystery Booster , playtest cards resemble the internal prototypes used by Wizards of the Coast when creating a Magic set