If nice airguns are a little hard to find in the typical American town, then locating the accessories that are specific to airgun field target competition is like hunting a herd of free-range unicorns. The following are the basics required to participate in Hunter Field Target (most beginners start off in this class).
Air rifles can range from sub-$100 ones to ones that cost more than $2000. Instead of talking about brands and models, let's start with what is needed.
Field targets can be placed at 10 to 55 yards, and the kill zone of each target can be reduced to less than 0.5 inches (or smaller!). This means that accuracy is an important factor. As a rule-of-thumb, a good airgun for field target should be able to shoot groups of 5 shots that can be covered with a dime at 25 yards.
This does not necessarily translate to expensive airguns, however. Any gun that can shoot dime-sized groups at 25 yards is a good candidate to have good fun in a field target match. To win, on the other hand, may necessitate some "investment".
Power is another factor to consider. Some airguns with low power has very good accuracy. As a general rule, 7 to 8 foot-pounds of energy at muzzle is a minimum. Otherwise, even a perfect hit will not have energy to knock the paddle over and count as a point!
In general, iron (open) sights are not advisable because the accuracy needed and drop compensation can be difficult with such sights. Furthermore, because a rangefinder cannot be used to gauge the distance to a target, the only mechanism to accurately range the distance to targets is the focusing mechanism of a scope.
These characteristics of a scope are extremely important:
First, the scope should have a parallax adjustable objective (AO) or side focus (SF). AO means the objective lens is adjustable via a ring on the front bell, and SF means it's adjustable from the side using a larger (and preferred) side wheel. This is not to be confused with the eye piece focus that only focuses the sharpness of the reticle. Also, there should be markings on the AO adjustment bell or side wheel on SF scopes to read the distance the user has applied to their scope, since the factory markings, if present, are seldom accurate.
Second, the scope should have sufficient magnification. Even in hunter division, the maximum allowed magnification is 16x. Even at this magnification, differentiating 50 yards and 55 yards can be challenging. The last 5 yards has a lot of pellet drop, and it is significant enough to lead to a miss.
Fortunately, there are many inexpensive scopes that magnify up to 16x and have AO or SF. If you are on a budget, choices from Leapers, UTG, Centerpoint or other related brands can get the job done.
Important: Make sure the chosen scope can focus down to 10 yards since there are shots this close quite often.
If you are shooting in the hunter division, you can use a non-attached bipod to support your rifle. There are many bipods on the market. You want to choose one that fits your rifle and has adjustable height.
The following are a few resources to help guide shooters who are looking for a few of the nicer "bits and bobs" particular to this activity. You'll find plenty more as you learn, but these will give you a start.
We add all the usual caveats: support local vendors whenever you can, there are many more vendors than we can show in a small list -- try to help support those vendors who support our activity. And remember, just because we list it here, doesn't mean you must have it today...or ever.
Airgun Depot -- http://www.airgundepot.com
Airguns of Arizona -- https://www.airgunsofarizona.com
Pyramyd Air -- http://www.pyramydair.com
Penchetta Pen & Knife -- http://penchetta.com/air-guns/
Trenier Outdoors -- https://www.trenieroutdoors.com/
Bog Pod -- available at many outdoor stores
Primos Trigger Stick -- available at many outdoor stores
Airguns of Arizona -- https://www.airgunsofarizona.com
Creedmoor Sports -- https://www.creedmoorsports.com
Rowan Engineering (UK) -- http://www.rowanengineering.com
Scope-Werks -- http://scope-werks.com
Airgun Stocks -- http://www.airgunstocks.com
Custom Stock (UK) -- https://www.customstock.co.uk
Champion's Choice -- http://www.champchoice.com/store/main.aspx
Creedmoor Sports -- https://www.creedmoorsports.com
Mac 1 Airgun -- https://www.mac1airgunshop.com/