Kanary definitely looks good - although they are US only at the moment (rules it out for me unfortunately). Thanks for your insight!

Yeah I think this it - it’s to accommodate companions; technically the ability is not on a card in your actual deck/battlefield (making Rule 10 not applicable?) but an extra deck mechanic like Un-set contraptions, stickers etc. (although I do not know how “assemble a contraption” works on the one legal contraption card?).

EDIT: Also the inclusion of “traditional card(s)” probably gives companion wriggle room.

I would say that pure monetary value does effect power but with highly diminishing returns and even at the lowest cost the synergy and construction of the deck is more important.

The most expensive card I own is Sheoldred, The Apocalypse - and I always take her out of my decks because she just doesn’t synergise with them. Yeah it’s powerful, yeah it doesn’t weaken my infect deck (for example), but a dirt cheap Blightbelly Rat is far more valuable to me in that deck if I want to do the things my deck is supposed to do, have fun, and have a good chance of winning.

Thanks for recommendation - that looks perfect; will try it out!