According to a well-known source*, the Canon EOS R3 and two new lenses, a RF16mm F2.8 and RF100-400mm are expected to be announced shortly; I would expect in the next two weeks. Both lenses are likely to be non L-series, but that’s not confirmed.
Canon hasn’t introduced a 16mm prime before in its history that I can recall, so this could follow one of several themes. Manufacturer’s like to follow established trends, but the RF system seems to be about breaking with the past. The most outlandish scenario would be a tilt-shift, replacing the current 17mm TSE F4L. The grapevine has been talking of an autofocus TSE, but with a F2.8 aperture, I can’t really see this lens as being a new tilt-shift. The more likely option is a wider version of the current non-L EF 20mm F2.8 USM; effectively a straight prime with no thrills. The third design could follow the RF 35mm F1.8 IS STM. Stabilisation wouldn’t add much in real terms but it would be useful at times.
According to the rumour-mill, the RF 100-400mm isn’t likely to be an L-series either. If we hadn’t already seen the RF100-500mm, then this would be the successor to the hugely popular EF 100-400mm F4.5-5.6L IS USM version. While, I would personally like to see a this RF model as an L-series, I fully expect it to be based on the current EF 70-300mm F4-5.6 non L. Still, Canon, and manufacturers in general, like to announce at least one high-end lens with a high-end body, so don’t rule anything out just yet.
As for the Canon EOS R3, it will be interesting to see if the rumoured sensor resolution is 24MP. It could be, if it’s intended to take on the current Sony A9 models, leaving the Canon EOS R1 to follow next year with a 50MP sensor to rival the Sony A1 and Nikon Z 9. We have a couple of weeks to wait to find out. I’m expecting a mid September announcement.