Grammarly
Grammarly Blog: All About Transition Words
Types of transition words and how they can be used to make writing more fluid.
University of Wisconsin
University of Wisconsin: Using Transitions: Transitional Words and Phrases
Tables of words that show different types of sentence transitions. W.9-10.1c cohesion/clarity/reason, W.9-10.2c cohesion/clarity/transitions. CCSS.ELA-Literacy.CCRA.W.4, W.11-12.1c Transitions/Cohesion, W.11-12.2c Transition/Cohesion....