SILUMGAR, DRIFTING DEATH Silumgar saw extensive play in Tarkirs first Standard outing, with its peak of popularity at the 2015 World Championships, where it saw extensive play in Esper Dragons
I also really love Glin, Dwarf Emissary for his ability to generate Treasure tokens, particularly helpful in color-fixing in a five-color deck
Marvel, Kamala Khan The no maximum hand size line on Ms
You can give an indestructible counter to a creature thats attacking, you can proliferate, and you can move level up counters around, so theres plenty of interesting stuff you could do with Tidus
Similarly, if The Soul Stone is already harnessed and becomes a copy of something else, it stays harnessed, though it's very likely that won't be relevant until that copy effect ends
Basically, youll always be able to play your commander assuming you have the mana available, so having a great one will make a tremendous difference in every game you play