Creating PowerPoint slide decks that are short but get your message across is hard. It can take hours to distil your pitch down to 10 slides for instance.
Check out this resource. It provides inspiration plus some really interesting slide decks to just make you think.
Even better, check out the Pitch Deck Examples section for examples of start-up companies asking for money from venture capitalists.
Looking back the original concepts look so hokey. For instance, Airbnb was originally called Air Bed & Breakfast and Tinder was called Match Box.
Also check out Uber.