Auslogics Disk Defrag. Also use their Registry Defrag. All free.

Defrag/HDD Monitoring Software section....
The contig/Power Defragmenter GUI combination is very good....![]()

Sorry, can't help as I've not used either of those, as O&O Defragger meets all my needs.
Do they both offer the same functionality? Are they the same price?
and both look good and have good reviews