We’ve held numerous parties over the years, games we play…
Shark Attack - kids all have a piece of newspaper (their island) to stand on. You tell them all to move around the islands and not stay still. When you shout “Shark attack!”the kids have to run and stand on piece of newspaper. Each time music play take away one newspaper island. Whoever not on a newspaper island is out. Winner is final child on an island. Alternatively you could play music and when that stops, they have to stand on newspaper island.
Put the kids into teams (18 kids into 3 teams of 6). Get 3 volunteers adults. Give kids a stash of newspaper and sellotape. Give them 15-20 mins to come up with the best newspaper costume. Winning team gets prize. Alternatively best adult wrapped like a mummy in loo roll.
Relay races - spoons with balloons.
Make paper airplanes - further one wins. Can give them 3 goes each.
Kim’s game - tray of random items, kids have a minute to look and then you cover up tray. Either get them to write down items or come up to you individually to say what on tray. Winner is one that remembers the most. You might want 3 trays on the go for this number of kids.
Chocolate game - throw dice - have to score six, put on hat and gloves (use adults gloves as bigger) and cut up chocolate with knife and fork to eat. Can only cut a square up at a time. Kids keep throwing dice until next person get six then they go. A noisy but fun game.
Pass the Parcel - suggest you split into 2 parcels with enough treats inside for every child to get at least one treat. For extra fun you could include a task they gave to do like “Hop on one leg until your next go”.
Throw beanbag into hoop/bucket.
Hope this gives you some good ideas.