NBA Free Agency 2020 has finally begun, and it has been an eventful one. With teams such as the LA Lakers and the Atlanta Hawks looking to be aggressive in the market, there have been more than just a few signings this off-season.With that in mind, here are the five most underrated signings so far in NBA Free Agency 2020.NBA Free Agency 2020: 5 most underrated signings this off-seasonHere, we will be listing some of the most quietly impressive signings that franchises have made during NBA Free Agency 2020. Additionally, the fit of the player with the team will play a major role in the ranking of the move this off-season.#5 Atlanta Hawks sign Rajon RondoRajon RondoAs mentioned before, the Atlanta Hawks have looked to be active in NBA Free Agency 2020, and the franchise has now signed two-time NBA champion Rajon Rondo.Free agent guard Rajon Rondo has agreed to a two-year, $15M contract with the Atlanta Hawks, sources tell ESPN.— Adrian Wojnarowski (@wojespn) November 21, 2020The 34-year-old will bring some much needed veteran experience and leadership into the team. Rondo is an exceptional passer, and could come off the bench in place of Trae Young. Additionally, his efforts on the defensive end will be a great asset for a team lacking in that facet of the game.Given what Rajon Rondo brings to the table, the Atlanta Hawks could improve dramatically next season.#4 Boston Celtics sign Tristan ThompsonTristan ThompsonIt was speculated in rumors that the Boston Celtics were looking to sign a versatile five in NBA Free Agency 2020. And the franchise has achieved exactly that by signing Tristan Thompson.The 29-year-old can switch between the four and the five. He is a great rim protector, and can also step up on the outside to lock a player down. On the offensive end, he is a very good inside presence and has great touch around the rim.Free agent center Tristan Thompson has reached an agreement with the Boston Celtics, his agent @RichPaul4 of @KlutchSports tells Yahoo Sports.— Chris Haynes (@ChrisBHaynes) November 22, 2020Tristan Thompson is exactly the kind of player the Boston Celtics needed, and the move will go down as one of the most impressive signings during NBA Free Agency 2020.