Basic Double Crochet Circle Pattern. for any placement or rug or whatever. so helpful!
Simple crochet circle pattern for single crochet in the round: How to Crochet a Flat Circle Using Other Stitches
How to Crochet a Perfect Circle // circles-comparison
cascadiacrochet: This awesome person made a chart for number of stitches for increasing for crocheting in the round. I love you awesome person. (source) Very helpful!
granny circle free pattern and tutorial
Wishing Well Crochet Square Moogly CAL 2016
Crocheted circle patterns
Coco Rose Diaries Blog
What you DON'T want: a visible join when crocheting in rounds. This tutorial shows you how to get an invisible join with crochet, using a great technique.