Hybrid is commonly referred to as a cloth diaper (an outer shell that can be reused) that has a disposable option. It's not uncommon for a cloth using family to use these while traveling so that they can trash or flush the inserts and not be carrying dirty diapers while they travel. G-diapers is a commonly known example of hybrids - it can either have cloth pads in it or a disposable (often flushable) pad. Others include Grovia and Flips - we've used all three of these diapers, but in the end they didn't make it into our final stash.
I will try hard not to gush about all-in-twos (AI2s) but they are my favorite. I will TRY to be objective. Here we go.
Imagine a diaper cover like you'd use with a prefold or fitted. Make an absorbent pad with a stay dry top. Make it so you can snap the pad into the cover. Now you have an all-in-two. As with prefolds and fitteds, you'd rotate between a couple covers in a day, but there is no folding or fastening the absorbent layer. They can come in snaps or velcro. They are often OS (with either a snap down design or adjustable leg elastic) but can come in sized options. For the review I'll be Using Softbums (Echo and Omni), Best Bottoms, and Ma Petite Mama diapers.
I'll admit I started my AI2 week a day early and I'll tell you why. They are so easy to travel with! They take up less space in the diaper bag because the inserts are slim and I just have one or two extra covers to rotate between. It also means I can fit more diapers in my wet bag (the bag that holds dirty diapers) as I often have to go more than 2 days without washing.
**WARNING** Softbums are my favorite with Best Bottoms coming in a close second. I might not be the best one to look at these objectively, but I'll try the best I can.