I don't know of any, but as you posted this in the iMac subforum and ask about USB 3 I'm going to assume you have an iMac with thunderbolt as well. The Apple thunderbolt ethernet adapters should be compatible with 802.3ad/LACP as OS X allows them to be bundled.
I learned that the below information, regarding some USB3 Gigabit Ethernet adapters and 802.3ad (LACP/Link-Aggregation):
### Supports 802.3ad, per mfg ###
none known, see note on USB31000S, below.
### Does not support 802.3ad, per mfg ###
UPDATE - DOES NOTE APPEAR TO BE 802.3ad compliant: Moshi USB 3.0 to Gigabit Ethernet Adapter UPDATE - OSX does not complain about it not being 802.3ad compliant, but I also didn't get link aggregation working on the Mac side: StarTach USB31000S - Technical Support: Unfortunately, we do not have support for 802.3ad on either of these USB adapters at this time.
StarTach USB31000SPTB - Technical support: Unfortunately, we do not have support for 802.3ad on either of these USB adapters at this time.
StarTach Other USB3 Adapters - Technical Support: I did ask about other USB based adapters with 802.3ad support and I do not have any other adapters I can offer at this time either.
I'd like to see if I can find one with pass-through, and will update this list.