I saw a concept ages ago and its been in my head ever since, a season dedicated to giving previous monsters/villains who have only appeared in the show once previous a second story, see where it goes if something could become a new popular monster.
My question to you is, who/what would you like to see make a return in this hypothetical season?
Slightly different but I’d like to see the War Seeds from Missy 3.2 make a re-appearence. For spolier reasons I won’t go far into it but they are an interesting idea.
Macra! The cameo in Gridlock doesn’t count or do them justice. 
No such thing
raston warrior robot i miss you <3
KROLL RISES FROM THE DEPTHS ONCE MORE!!!
Or Axos… Let’s go with that one 
The Voord. Yeah, I know they’ve been in a couple audios and comics, but I’d love to see them return to TV.
I think that a return of the Yetis could be fun. Maybe even with a recasted second doctor.
Very good idea for a season, I want the Meddling Monk, Chumblies and Quarks - possibly all together in a big plot 
And I know they’ve been in more than one TV story but they weren’t the focus - I’d like to see another invasion attempt by The Silence!
You’ll definitely want to check out UNIT: Silenced then.
Yes, that’s on my list (not listened to any UNIT yet). It’s a long list.
Krillitaines are one of the big ones for me
That would be great. As they are an ever evolving species you could have them appear however you want.
ooh yeah they’re ones I’ve wanted to see again in a different form most likely
I second the Voord.
I quite enjoyed the Skithra.
Do the Silence really work on audio? They are not exactly a talkative bunch…
I could see there potentially being something interesting to be done with other Stenza at some point
They work better than you’d think. It especially plays with the memory aspect of them.
Meglos! we want more cactus people 
They actually really do - I found UNIT: Silenced properly scary, not helped by the fact that the Silence scare the pants off me to begin with! But yeah, one of my favourite UNIT boxsets for sure