Flier: Thunderbolt or Marauder
Tank: Valdor, Macharius (preferably Heavy Tank or Vulcan) or Stormhammer
Artillery: Minotaur, Praetor
These are probably the ones I would consider. None of them except the Thunderbolt is spectacular, but mostly average to solid. Which one to choose depends on what kind of army you'd like. Talking from a lore perspective however, as gamewise Baneblades or just normal heavy support are probably better picks.
The Macharius is mostly a poor man's Baneblade in lore, being worse but easier to manufacture. The Praetor is a rare and sophisticated artillery vehicle, while the Minotaur is even more rare, being "all but unknownon the battlefields of the 41st millenia". The Valdor is also considered very rare and most Forge Worlds lack the ability to manufacture one, and it being only used by the most venerable armoured regiments. The Stormhammer lacks good lore for
40k, but it's probably a bit more rare than the usual Baneblade chassis. Thunderbolts and Marauders are both incredibly common vehicles.
If you have a Baneblade or are planning to get one, I think the Stormhammer would be the best choice, as the others ones would look pretty small compared to the plastic superheavy. If not, most of them would fit but be aware that they Malcador variants are not that much bigger than Leman Russes, for better or worse (I actually like that the smaller size makes them fit in better).