The following list is presented in alphabetical order, not necessarily in order of preference.
For the purposes of this collection, I will include only manufacturers whose guns are specifically called "turkey guns," or those which have a camo finish and are suitable for turkey hunting. Many of these guns are available in traditional finishes as well, which does nothing to hinder their effectiveness on turkeys - but if they are included in this listing then they were, at the time of publication, available in camouflage finish and suitable for hunting turkeys.
Benelli makes a variety of turkey guns, all of them camo. They make 'em in pump (Nova, SuperNova) and semi-auto (M2, Super Black Eagle II, Vinci, Super Vinci) actions. Many of their turkey guns have a pistol grip on the stock, which they call the SteadyGrip™. Available in 12 gauge (3" and 3.5") and 20 gauge. At least some of these models come from the factory drilled and tapped for scopes or red dot sights.
Beretta's turkey guns are not particularly called "turkey guns" by the company. They are included here because they are available in camo finish. All of them are 12 gauge autos (semi-automatic). The AL391 Urika 2 is chambered for 3" shells, while the A391 Xtrema2 is chambered for 3.5" shells.
Browning offers camo shotguns in auto, pump, over/under, and even bolt actions. All actions offer a choice of 3" or 3.5" chambers. BPS pump guns are available in 10, 12, and 20 gauge, and certain models feature the NWTF (National Wild Turkey Federation) logo and fiber optic sights. All BPS turkey guns are drilled & tapped for scope/red dot sight. Mossy Oak and Break-Up camo patterns.
Franchi's auto model I-12 is available in 12 gauge (3" chamber), and the 720 is currently listed only in 20 gauge. Franchi doesn't offer a 3.5" chamber model, although in the past they offered the 912. As of 2011, their website doesn't offer any "turkey" guns at all - look under "waterfowl" to view their camo scatterguns. Realtree® APG HD™ and Advantage® Max-4 HD™ patterns.
5. H&R 1871
H&R has long made some of the most practical, simple guns there are. Their break-open single shot shotguns are familiar to many of us, and have started many a hunter on his journey to becoming a true sportsman. These days, they're called both Topper and Pardner, and you can even get one in camo.
They also market a semi-auto model called Excell, which is available in a turkey-specific model - and an H&R Pardner pump shotgun, which is certainly confusing (now they have single-shot and break-open guns called "Pardner"). Remington owns this company, and the Pardner pump is said to be a made-in-China almost-clone of Remington's 870 pump gun.
Camo patterns vary (some name brands are listed, others don't say).
6. Ithaca Gun
Ithaca's legendary model 37 pump shotgun is the backbone of the current company. In fact, the model 37 is their shotgun lineup. Currently, they offer the Turkey Slayer. Stock choices include black or camo synthetic of traditional styling, or a thumbhole stock made of laminated wood. This model has a 3" chamber, and probably only available in 12 gauge.
Mossberg offers 12 gauge turkey guns in pump and auto actions. Pumps include models 535 (3.5"), 835 (3.5"), and 500 (not specified, probably 2.75"-3"). They even have a camo Model 500 Bantam, for smaller hunters. Autos are the 935 (3.5") and the 930 (2.75"-3"). 500s can be had in 12 and 20 gauge, and .410 as well.
Camo pistol-grip and traditional stocks are available in most or all models, and some camo thumbhole stocks are also available.
One of Mossberg's best and enduring features is the placement of the safety - on the tang where it belongs, worked by the thumb from either side (ambidextrous). Too bad they use those stupid "tamper-proof" screws to install them.
Available camo patterns include Mossy Oak, Realtree, and Advantage.
Remington lists a number of turkey guns on their Web site, both pump and auto. Pumps include the old model 870 (3.5" versions are available) and the much-newer 887 (I think all of these handle 3.5" shells).
Semi-auto Remington turkey guns include the 11-87, SP-10, and VERSA MAX™ models, some of them available with funky thumbhole stocks. The 11-87 and VERSA MAX™ are 12 gauge, while the SP-10 is a big honking 10 gauge sucker. Camo patterns vary, and include Mossy Oak and Realtree.
Weatherby currently lists their SA-08 semi-auto shotgun in only one camo model - a waterfowl version with Mothwing® Marsh Mimicry® camo.
Winchester's former line of pump guns was discontinued when they closed their New Haven factory, but now they're offering a new one, called the SXP. While it's not listed in a specific model for turkey hunting, it is built there (made in Turkey).
Their semi-auto is now the Super X3, which comes in a number of camo versions - including one called the NWTF Extreme Turkey.