I agree with ageofglory about GNW ranges. When I researched the period I found out that many uniforms were mostly generic and a lot of figures from other ranges will fit Russians. I also have an advantage over many people of being able to read Russian. I found out that Russians ordered their uniforms from all over Europe and variation in cut and equipment existed even in a single unit.
Check Old Glory Marlburian range, they have generic packs that will work for Russians also. Any collarless uniforms will do. OG figures in that range are very good. For figures without tricorns use Foundry.
Also, there were many variations in grenadier hats, just do your research and choose which OG or Foundry pack will work best. There were variation in a single unit as well.
Major difference between Swedes and Russians are turnbacks – Swedes had them, Russians possibly didn't have them in the beginning. Any Marlburian figures with turnbacks will work for Swedes. I didn't check Old Glory packs suitable for Swedes, but Musketeer and Foundry make them. Judging from Viking figures I have from Musketeer they should fit with Foundry and Old Glory sizewise.
Another major manufacturer of Marlburian figures is Front Rank. They are big figures and will not mix with anything else.
The best dedicated range for the period I found is from plastic Zvezda company. They are 1/72 scale and I highly recommend them. You can supplement them with Strelets figures (for karpus wearing figures), they mix fine in the same army, not necessary in one uniformed unit. 1/72 scale are bigger than 15mm and almost as big as 25mm and also cheaper. Quality of Zvezda miniatures is better than anything I've seen in 25mm ranges. Zvezda doesn't have Russian cavalry yet, but they should have them soon or use Strelets figures.
Reiver castings look like some of other Old Glory ranges. They do not look very good in unpainted state, but look fantastic painted and based as a unit. It will take some work to fit cavalry on their horses, judging from what other said, but they have a good range, IMO. I never dealt with that range, just observing from photos in magazines and what others said.