Here's a PDF containing some basic rhythms which can be used to create some fills. Not only do they sound great but they are extremely applicable across a variety of genres and tempos.
Above each example I've written a phonetic such as Tea for Quarter Notes (Crotchets) Coff-ee for a pair of Eighth Notes (Quavers) etc.
Use this as a jumping off point. If you're new to sight reading it's best to go over them with a musician that is already an accomplished sight reader.
Some people dispute if phonetics can be used to accurately learn rhythms but the only problem I've ever encountered is when people pronounce a phonetic with a varied rhythm to what it should be. For example, Coff-ee should be pronounced with two even syllables however you could easily mistakenly pronounce it another way (a longer first syllable and a shorter second) therefore the phonetic wouldn't match up with the paired rhythm.
Practice each example along with a metronome at a comfortable speed. If you can add in a stepped Hi Hat so you can feel the pulse.
Once you can accurately play these fills orchestrate them around the drum kit at varied tempos.
You can also use these phonetics to create grooves which I will demonstrate in a following lesson.
Have fun, the possibilities are endless!