Have you looked on their actual website (and not through YouTube)? That way, you can search for the type of workouts you are looking for (HIIT, core, length for example).
My favorites are:
the HITT like a girl (there are 2)
HITT the deck cardio
When I say jump HITT
Red light, green light workout
Any of their pilates workouts
Plus tons more
Now if you want to look for these specific workouts, it'll be easier to find through YouTube because you are searching its name. However I highly recommend you watch the videos through their website so that they remain free
what workouts do you like to do? Their search engine on their website is awesome. And if you really like them, I highly recommend their 1 or 2 month workout schedule (this you need to purchase though VERY affordable) since it lays out what to do on a daily basis. They have a lot of schedules.