Here is a compilation of a few different plastic impact sprinklers of various makes and models, all being an above-ground mounted head.

First up is an older Rain Bird P2-PJDA-C low pressure impact sprinkler that was made sometime in the late 1990s. These heads perform very well in the lower pressure range where most others fell short, although it does not do well above 45 PSI due to the light arm spring in it. They were one of the simplest part-circle impact designs made by Rain Bird, with very few moving parts and a one piece reverse lever that does not use a spring to trip. These sprinklers are rated for 2.2-4.7 GPM at 10-45 PSI with a range of 24-41 feet.

Next up is a rather unique impact made by Naan, known as the model 435 "Topaz" sprinkler. These were once sold in most hardware stores such as Ace Hardware back in the early 2000s, and are a more robust design than the typical cheap all-plastic impact sprinklers of the time. They are incredibly fast rotating sprinklers much like the cheaper models except they have better wear surfaces for a much longer life. The 435 was rated for 2.6-5.6 GPM at 15-65 PSI with a range of 34-48 feet.

Third in line is the once-popular Beta-II plastic impact sprinkler made by L.R. Nelson. These were once a very common sprinkler to find in use on many lawns across the country, mounted on many different types of hose-end sprinkler bases. They also came in a popup version during that same time period and were pretty popular in certain regions of the country. These Beta-IIs were of great quality for their time being made of all plastic components and aren't nearly as fast as most other plastic impacts out there. These were rated for 2.9-4.0 GPM at 30-60 PSI with a range of 36-43 feet.

Last (but not least!) is one that anyone else would have probably thrown out due to the broken arm but as you can see it still keeps on kicking. This is an older cheaper plastic impact sprinkler made by Lego/Water-Whiz back in the 1990s and early 2000s, which is a model 7220 with the blue fixed nozzle installed. These were once sold in most home improvement stores (mainly Lowe's) before Lego/Water-Whiz went out of business, and also came in a popup version known as the model 7329. These were rated for 2.0-3.4 GPM at 20-60 PSI with a range of 32-40 feet.