Depending on which YYE trick list you follow, you might not encounter a 1.5 mount until you get to McBride Rollercoaster. The mount didn’t come easy to me, so I was searching the forums for other posts asking for help and found this one with a video from @G2_Jake doing Pitch and Catch. That seemed like a pretty accessible trick and will definitely get the 1.5 mount practice in because you basically just hop in and out of it until you run out of spin.
This was the topic/post with some other good links and tips for 1.5 mount:
If only I knew to jump to Buddha’s Revenge and then go back to McBride Rollercoaster back then!
And, I’m not really sure if this qualifies as a combo, but while I was trying to get Kwijibo down, I started doing this mix of Buddha’s Revenge, Eli Hops, Pitch and Catch and a redirect (that might have a name that I don’t know) that is essentially a Pitch and Catch where you miss the catch and redirect it back to the 1.5 mount it started from (with thanks to @ilinx_toys Ross for showing that to me when I was practicing 1.5 mounts last year).