It seems that most of the high-end external SSD enclosures and external SSDs support UASP and TRIM/UNMAP.
Wikipedia does mention thumb drives but provides no further details:
USB Attached SCSI (UAS) or USB Attached SCSI Protocol (UASP) is a computer protocol used to move data to and from USB storage devices such as hard drives (HDDs), solid-state drives (SSDs), and thumb drives. UAS depends on the USB protocol, and uses the standard SCSI command set. Use of UAS generally provides faster transfers compared to the older USB Mass Storage Bulk-Only Transport (BOT) drivers.
However, I found nothing about usb flash drives that would support UASP and TRIM/UNMAP, despite there being a few high-performing flash drives that are marketed as having the "performance, capacity, and reliability of an SSD".
Are there any UASP USB flash drives with TRIM/UNMAP support?