GTX 900 Series
Released in 2014, The 900 series of GPUs was the first to use the new "Maxwell' architecture and was the successor to the Geforce 700 series. There are 5 cards in the series as well as "Ti" (Titanium, meaning higher performance than the non-Ti model) version of the 980. Though released 6 years ago, there are still many in service today.
GTX 1000 Series
Released in 2016, The 10 series of GPUs was the successor of the 900 series and featured the revolutionary new "Pascal" architecture. A total of 7 cards have been launched, with advanced editions of each also available. The 10 series is by far the most common dedicated GPU series, featured in a vast array of computers, both consumer and professional.
GTX 2000 Series
Released in 2018, The 20 series of GPUs was meant to replace the 10 series, though its success at doing this is debatable. The GPUs feature "Turing" architecture and come in 4 models, with both Super and Ti variants available for some cards. The 20 series was the first to feature ray-tracing but came with marginal performance increases and a hefty price tag. A lot of consumers (including myself) chose not to buy one and instead waited for the next generation.
GTX 3000 Series
Released September of 2020, The 30 series of GPUs is the latest generation of cards and boasts significant performance increases over the previous generations. So far, 3 cards are being sold with more likely to be released in the future. The cards feature Nvidia's new "Ampere" architecture and are a clear jump from the 10 series, presenting a much more appealing price tag than what the 10 series sold for. There is high demand for the cards and it is very difficult to buy one due to supply shortages across the world.