Tyvar does lack any ability to protect himself really, or to directly engage with your opponent, so he is more of an engine support piece, but hes a highly interesting one
We can't afford to run out of tokens, so somehow we have to keep them safe
Its promotional card status, energy cards attached, and brilliant design earn it an essential spot in the card games, having, in the past, dealt opponents powerful blows in competitive matches
Varchild, Betrayer of Kjeldor could be fun in some sort of group slug deck where you give your opponent tokens but in a harmful manner (maybe with something like Trespasser's Curse on the battlefield), although she might be better in the 99, since mono-red is pretty limiting
Modern Special Illustration Rares and Alternate Art cards from Sword and Shield onward regularly sell for hundreds of dollars, proving that recently printed cards can compete with vintage ones in terms of price.