I use the yongnuo 560

YONGNUO YN560 IV Wireless Flash Speedlite Master + Slave Flash + Built-in Trigger System for Canon Nikon Pentax Olympus Fujifilm Panasonic Digital Cameras https://smile.amazon.com/dp/B00PGTOX26/ref=cm_sw_r_cp_apa_ZEe9BbWQAM1CS

If you can get without TTL there are the yongnuo flashes, I've personally tried the yn560iv and the yn685 with their triggers. As for triggers you should use the YN560-TX. All of these must be the Canon versions (not the nikon ones).

With the trigger you can set your flash(es) parameters from it (without touching the flashes themselves) which is a big advantage once you've set the flashes in place, maybe inside a softbox, etc.

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Don't buy the yn-622c-tx which, while it works on canon bodies, and it even gives you TTL with the yn685, doesn't even fire the flashes on M43 cameras, at least not on the olympus E-M10 and the Panasonic Gx85.

I've tried all of the above-mentioned yongnuo products on both of these cameras (E-M10 and Gx85), I'll add some amazon links to the products, I hope they can be helpful

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https://www.amazon.com/dp/B00PGTOX26/ref=sxts_kp_bs_1?pf_rd_m=ATVPDKIKX0DER&pf_rd_p=8778bc68-27e7-403f-8460-de48b6e788fb&pd_rd_wg=xMKtJ&pf_rd_r=Q1W0BDPWVAHWKBY1N9CE&pf_rd_s=desktop-sx-top-slot&pf_rd_t=301&pd_rd_i=B00PGTOX26&pd_rd_w=XGvyX&pf_rd_i=yongnuo+yn560+iv&pd_rd_r=1c36158b-ccf3-4d7c-b5e6-2c40cbbb898a&ie=UTF8&qid=1543588353&sr=1

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https://www.amazon.com/YONGNUO-YN685-System-Wireless-Speedlite/dp/B0159PJL8C/ref=sr_1_1_sspa?ie=UTF8&qid=1543589021&sr=8-1-spons&keywords=yongnuo+yn685&psc=1

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https://www.amazon.com/dp/B00KM1QZRY/ref=sxts_kp_lp_3?pf_rd_m=ATVPDKIKX0DER&pf_rd_p=8778bc68-27e7-403f-8460-de48b6e788fb&pd_rd_wg=xMKtJ&pf_rd_r=Q1W0BDPWVAHWKBY1N9CE&pf_rd_s=desktop-sx-top-slot&pf_rd_t=301&pd_rd_i=B00KM1QZRY&pd_rd_w=XGvyX&pf_rd_i=yongnuo+yn560+iv&pd_rd_r=1c36158b-ccf3-4d7c-b5e6-2c40cbbb898a&ie=UTF8&qid=1543588353&sr=3

I have used this Yongnuo flash on my E-M10 as well as off camera, being controlled by the 560-TX unit you listed.