Oo, terrific list! Some thoughts below.
Frontier in Space is one of thoe Mac Hulke gems with a solid cast, the Draconians were delightfully realised in prostetics at the time. If there’s another intriguing diplomacy thriller being written, they’d fit right in.
Krotons sare a bit one-note, but if played off well they could make for another solid story about the danger of limited/selective learning.
Not sure what could be done with Mechanoids, but expanding upon their massive city and history could be fun. (Also could be an excuse to fill the annual Dalek quota the BBC has to do to retain the usage rights.)
I’m a sucker for black hole related stuff, so while I don’t know if anyone with the spellbinding theatricallity of Stephen Thorne exists these days to play Omega, another story with 'em could be fun, maybe some twists or more changes to known history, espcially with today’s budgets.
Rutans are a hard yes. Horror of Fang Rock isn’t a frequent rewatch, but it’s a solid tory, and I want to see mroe of the smug jelly-fish-like creatures. Especially if mixed with my favorite Sontarans since the two by OG Lindsay, the Flux ones, the dialogue/interplay could be fantastic.
Sensorties are a cool concept stuck in a clunkily directed/scripted serial, (Associate Prod. Mervyn Pinfield’s four episodes are a chore to sit through, he was not suited for TV directing. Thankfully Frank Cox 's chops salvaged the last two.) It’d be great to see the Sensorites get a more in-depth look, lots of sociopolitical intrigue to dig out there.
The Black Guardian, and the Guardian lore in general would need to be handled very carefully, ideally as the framing for another small multi-episode quest, but with a more modern/seculalr spin to flesh out their motivations.
The Toymaker is a 50/50, design-wise and vibe, it’s just too dated outside the 60’s, but I’m one of the few that likes silly games with some sinister stakes to them mixed an ensemble cast getting to act weird, so if the Toymaker was brought back again (outside of BF Season 22 recreations), I’d be curious to see how they improve on the character.
The Mara could certainly be realised better with mroden SFX, but that monster is intrinsically tied to Tegan AFAIC, so I’d prefer it to involve her in some way (again like with BF).
The Meddling Monk is a big fat YES, BF has been taking that character in some great directions, I’d love to see an interation for the show itself, could make for more great historacal/sci-fi fusion stories the show has a penchant for.
The Rani also is a big yes, especially if they take the gaudy mad scientist angle up to eleven. (I’ve always thought 4’s What’s it all for?! speech in Pirate Planet could easily be re-tailored into something vs The Rani)
The Valeyard could work, though the BF Last Adventure set is kinda the perfect wrapup to Sixie & The Scrapyard’s storyline. Though I’m open to see what’s done if so!
I’m down for both new & old monsters showing up. I don’t know if they could do Sutekh without Gabriel Woolf, but some more Doctor vs Osirons would be interesting!