The firm Datadecals produces one beautiful decals sheet for 1/32 Trumpeter kit, and another sheet is arriving.
A sample was kindly sent by the firm owner, Mr. Adam Batkiewicz.
 

The sheet DD32001 shows five late version aircrafts, all described in the profile pages of this site too; black 12 Smert to Nemetsim Okkupantim red 02 white 54 Za rodinu       The instructions sheet is very exhaustive, with color profile and upper views, and written comments about the photos from which each profile is taken.  This demonstrates a good and original research work. In my opinion, some of these aircrafts should have stars with thin black outline.

The sheet is neatly printed and well centered, on a very thin trasparent film that will be nearly unvisible on the painted model; I think that such thin films will require an extreme care in positioning, avoiding softener liquids. The sheet includes thin white lines for correcting eventual out of register white outlines, and a piece of red scrap decal to help for adapting it to movable surfaces.         The sheet DD32002 has further examples: white 12 black 36 yellow 27 (in my opinion, the number should be red) white 44 white 64

The Czech firm Eduard produces an adhesive mask set to protect the canopy, the landing light and wheel disks (or position lights?) of the Trumpeter kit, 1/32. I don't understand well  how it functions from this scan, but I think to see that no mask has been provided for two stripes behind the rear sliding hood frames, that should remain trasparent (even if this is not written on the kit's instructions sheet).

The French firm Contact Resine has released a detail set including:
 

complete cockpit interior details, including resin floor, sidewalls, seat and photoetched instrument panel with decals; I have to say that, where the seat and floor are better than those of the model, the sidewalls have to be rejected because there should be a wide space between the tubes strut and the curved side panels, and this can be obtained better by working on the pieces of the Trumpeter kit; radio deck; it looks much more beautiful of that of the kit, but it is less in accord with available drawings; besides it looks that on the most of MiG-3s the radio was absent or only partially installed; resin elevators and rudder; while they have an excellent reproduction of the fabric skinning, they have no traces of hinges; no ailerons are provided, although the pieces of the kit have the same unhappy reproduction of the fabric skin of its rudder and elevators; resin wheels; they are a bit more detailed than those of the kit, but the disks are a bit too flat, and some bolts should be removed; the tyres are flattened, but they don't look wider on the sides of the contact to the ground; resin propeller, with thinner blades and slightly more conical spinner than the pieces of the kit;

photoetched flaps and struts; this should give a far better result than the pieces of the kit, if one is able to build them; landing gear doors pieces to replace or improve the kit parts; they could be useful, in consideration that the parts of the kit are poor and full of extractor traces; details to improve the water coolers, apparently good; wings for the underwing rockets, detailed on one side only; many small details for cockpit, landing gear and oil coolers; double adhesive mask for canopy (for internal and external side?); a color decal for instruments.

A sample was kindly supplied by Marc Guerrero

The Polish firm Montex has a set of  adhesive plastic masks both for canopy frames and for external markings. Their site has an excellent page with instructions on how to use masks, and a page with links to distributors of their product.