Nice ideas for toddler bedroom?

[Haaaaaaan]

My 14 month old's room is a bit bland and I'd love to do some silly fun stuff while he's still little that he will enjoy. I'm thinking wall stickers, maybe one of those little car shaped bookcases or something. I'm just rubbish at decorating and can't decide what to do! The available floorspace is about the size of a double bed + 50cm (until recently the bed was there so it now looks a bit empty).
Do your kids have anything they really loved? I was wondering about big animal soft toys as well but they were pretty expensive.
I can't decide whether to try to have a 'theme' (like jungle animals or vehicles), or just get whatever crap I can off FB marketplace and see what he likes!
He has open shelving at the moment, a tall wooden bookcase with the upper shelves for nappies wipes and other handy bits, lower shelves for toys although not many as he mainly plays downstairs where I can watch him. Maybe just painting that a fun colour would help?

A wigwam?

wall stickers are definitely good.

don't bother with a theme - kids change their mind about what they like very quickly.

a pop-up play house can be great, especially with a whole lot of cushions and cuddly toys inside.

does he have a bookshelf with some board books?

Ooh we have a wigwam someone gave us, and random cushions used for breastfeeding, I will put them up. He has a few books in there on a shelf with his toys.

Go to the kids ikea. Loads of giant stuffed animals that aren’t silly money you can shove in the wigwam and plenty of other cool stuff- biggest hits for us was the rug with roads on it and the ikea garage and cars that are chunky so no small parts you need to worry about. They also have a small bookshelf that’s at kiddy height. Do not get wall stickers. DD had them from John Lewis so you’d think they’d be ok quality but when she fancied a change a couple of years later the walls were wrecked peeling them off. It also gave her the idea that stickers on walls = ok and we had to repaint the entire room much sooner than we’d have liked.

We used wall stickers and have a bookcase in there. DS is 5 now and still doesn't really do anything other than sleep in his bedroom so it's fairly bland. As he gets older, we'll let him decide what he wants to do with it.