Amazon.com : KACALLAP 2.4G Wireless Flash Trigger A530S Universal for Canon/ Nikon Cameras with Hot Shoe &Speedlite,Such as 5D Mark IV/III,70D,EOS Series Cameras : Electronics
Amazon.com : Altura Photo Professional Flash Kit for NIKON DSLR - Includes: I-TTL Flash (AP-N1001), Wireless Flash Trigger Set and Accessories : Electronics
Amazon Sells This $28 AmazonBasics Flash for Canon and Nikon DSLRs | PetaPixel