There are plenty of accessory and lens deals at BHphoto (click here and scroll down to see them all). Here are a couple of special mentions:
Lenses and Adapters:
20% off on the Vello Deluxe Auto Focus Extension Tube Set for Sony E Mount.
$300 off and 4% reward on the Zeiss Touit 12mm f/2.8 Lens
$30 off and 4% reward on the Sigma 30mm f/2.8 DN E-mount Lens
20% off on the Vello EXT-SFEE Econo Auto Focus Extension Tube Set for Sony E-Mount Lenses
Lights:
$385 off on the Bolt VB-22 Bare-Bulb Flash Kit with Cyclone PP-400DR Power Pack
20$ off on the Bolt VM-210 Flexible Macro Light
Tripods:
$200 off on the Oben CT-2491 Carbon Fiber Tripod
$30 off on the Vanguard Alta Pro 263AB 100 Tripod W/SBH 100 Ballhead
$70 off on the Sony VCT-MP1 Monopod
Bags:
$35 off on the COSYSPEED Camslinger 160 Mirrorless Camera Holder
$44 off on the Think Tank Photo CityWalker 20 Messenger Bag
$30 off on the Lowepro SlingShot 302 AW Camera Bag
$35 off on the Lowepro Passport Backpack
Cards:
$20 off on the Sony 128GB M Series UHS-II SDXC Memory Card (U3)
Extras:
$3 off on the Expert Shield Crystal Clear Screen Protector for Sony Alpha a7R II Digital Camera