By building a Cat Commander deck, the designers had a chance to push the creature type to more tables
For those who enjoy pick n mix decks like The Ur-Dragon or Morophon Changelings, Rukarumel lets you hone in on one creature type while benefiting from all that Slivers have to offer
When I first saw it my mind went to combo lines with it
As far as niche creature commanders go, Zeriam is pretty solid
Aberrant Abolish Ainok Survivalist Appetite for the Unnatural Artisan's Sorrow Aura Shards Aura of Silence Break Asunder Break Down Broken Bond Capashen Unicorn Cathar Commando Caustic Caterpillar Cindervines Citizen's Crowbar Coliseum Behemoth Conclave Naturalists Containment Breach Crack Open Decommission Deconstruction Hammer Deep-Fried Plague Myr Destructive Revelry Devout Witness Disenchant Dismantling Blow Dispeller's Capsule Expose to Daylight Filigree Fracture First Pick Flaxen Intruder Flaxen Intruder Foundation Breaker Fragmentize Frenzied Trapbreaker Freyalise, Llanowar's Fury Gemrazer Gemrazer Gleeful Sabotage Grist, the Plague Swarm Harmonic Sliver Hivespine Wolverine Hopeful Initiate Indrik Stomphowler Inspired Insurgent Invoke the Divine It's Clobberin' Time
This card requires you to deal combat damage with it to a player, but you can return a creature with 3 or less power to the battlefield