Bobbly pompom edging.
These are UK terms.
4tgr = treble crochet 4 together
Yarn over (YO) hook, insert hook in stitch (st), pull up a loop, 3 loops on hook. YO hook, pull through 2 loops, 2 loops on hook. YO hook insert into st, pull up a loop, 4 loops on hook. YO, pull through 2 loops, 3 loops on hook. YO hook insert into st, pull up a loop, 5 loops on hook. YO, pull through 2 loops, 4 loops on hook.YO hook insert into st, pull up a loop, 6 loops on hook. YO, pull through 2 loops, 5 loops on hook. YO pull through last 5 loops.
Essentially this is the pattern:
*Ch7, 4tgr in 4th ch from hook, ch1, ss into bottom of cluster, ch3, skip 3 st and ss into next st.* repeat around.
I used https://zeensandroger.com/2016/03/14/a-touch-of-spice-with-a-pompom-edge/ as the guide for the pattern.
and here is a Youtube Video