The list for fundraising ideas is endless, but have a look at some of the more popular ways people fundraised before.
The main tip that previous fundraisers can give you is DO SOMETHING YOU ENJOY! If you don't like baking, do not organise a bake sale! Doing something that you enjoy (i.e. football, running, crocheting items, cooking) and turning them into fundraisers will be far more successful as you will be passionate about making the event work and dedicating the right amount of time to it.
Another top tip is to make your chosen fundraiser creative. For example, if you want to do a running challenge, maybe do each run in fancy dress and document your outfits via social media. If you like baking, then do a bake sale with a certain theme (like Star Wars themed bake sale on May 4th). Twisting a traditional fundraiser and making it your own stands out and engages people more.