I'm sure many of you have heard of this resource, but on the off chance you haven't your in for a treat: FCCR (Florida Center for Reading Research) is a wonderful resource for all things RTI.
This website is set up with tons of free resources for many of the phonics and reading skills all students need. The resources are put all together. Divided by grade level and topic. Annnd for my slightly organizing loving self if printed in color the topics are color coordinated. Swoon.
Topics for K-5: Phonological Awareness, Phonics, Fluency, Vocabulary, and Comprehension, with varying degrees of skill levels depending on the grade. Just choose a topic, find a corresponding activity you think will work for you, download, print, cut, and use!
I've utilized this website in my MTSS groups as well as when covering reading skills in center rotations during the day!