Image Ads: Static image with text headline/link.
Video Ads: For catching attention, especially if you have something dynamic or product demo-like.
Carousel Ads: Multiple images or videos in one swipeable ad so you can tell more of a story or show multiple products.
Free-Form Ads: Longer text plus images/GIFs/videos, more like a deep post than a typical ad. Good for when you want to explain or engage.
Conversation Placements: These show up in comment threads/discussions. More niche but very Reddit-native.