All the old ones:
musical chairs/ statues,
pass the parcel - you can put forfeits in between layers and just one prize in the middle, and have 2 parcels for a big circle,
a treasure hunt - perhaps split children into teams, and they each search for say 10 tokens (clothes pegs or similar) in their team colour, hidden in one room or garden, which can be exchanged for a prize at the end. Stops them fighting over tokens as they are working as a team,
games like over/under - line kids up in 2 teams(or just 1). They stand one behind the other, the first child in each team holds a ball. On your shout/whistle, they pass the ball over their head to the person behind, who passes it between their legs to the person behind them and so on. When it gets to the person at the back they run to the front of their line and it continues as before. When the original leader is back at the front of their line the team sits down to show they have finished and they have won.
Also you can make the party more exciting with an easy theme like pirates or animals - you can get cheap cardboard masks or hats, themed food (animal biscuits, crisps and snacks in pots lablled "Lion Food", "Shark Bait") or even enlist some help and do a little bit of face painting.If you do pirates chocolate coins make great treasure and prizes.
Also maybe play sleeping lions when they are a bit tired - everyone pretends to be asleep on the floor, and you walk about. When you see someone move you tap them on the shoulder, they are then awake and they help you look for people moving. The last sleeping lion is the winner.
Apple bobbing, even when its not halloween or maybe fishing with a net in a small paddling pool or large bowl (baby bath) for apples or tokens they can swap for chocolate coins or similar.
Hope some of this is helpful, i'm sure oyu could find a good book with lot more ideas but i know that these work quite well generally, so long as you change from one to the other quite quickly. They generally like the competition and cos the games are active they gt tired sooner (hopefully) and the party doesnt have to go on as long. Hope some of that massive post is useful, good luck!