The Mandalorian season 2, episode 2, "The Passenger," sees Din Djarin providing an interstellar taxi service to a Frog Lady with a precious cargo of eggs - and it's actually not the first time we've seen her in the show. Both Frog Lady and Dr. Mandible made an appearance in The Mandalorian season 1, episode 5, "The Gunslinger."
Mando has spent quite a bit of time on the desert planet of Tatooine, where both Anakin Skywalker and Luke Skywalker were raised. Among the familiar places he's visited is Mos Eisley cantina, the rowdy bar where Han Solo shot Greedo (regardless of whether or not Greedo shot first) in Star Wars: A New Hope. Obi-Wan Kenobi famously said of Mos Eisley spaceport, "You will never find a more wretched hive of scum and villainy." Indeed, when Mando showed up there looking for work in The Mandalorian season 1, he ended up teaming with the very scummy and villainous bounty hunter Toro Calican.
The introduction to Mos Eisley cantina in "The Gunslinger" features a few shots of the gathered patrons, and among them are two who get an expanded role in "The Passenger." There's Peli Motto's gambling opponent Dr. Mandible, an ant-like creature who helps Din Djarin out with a lead when he's searching for other Mandalorians. And there's also the Frog Lady herself, who doesn't have her tank of spawn with her just yet. It appears that both of these aliens are regulars at the Mos Eisley cantina, though this regularity hasn't given Dr. Mandible the skills he needs to beat Motto at a game of sabacc.
It's possible that The Mandalorian's showrunners already had a bigger role in mind for Frog Lady and Dr. Mandible, and their cameos in season 1 were designed to set this up. However, it may also simply be the case that they loved the creature designs so much, they wanted to give them more than a brief moment on screen. Frog Lady's interactions with Mando in "The Passenger" are certainly compelling - whether it's the frustrations that both of them experience due to the language barrier, or Frog Lady's horrified reactions to Mando's evasive maneuvers when trying to outrun two New Republic X-wing pilots.
"The Passenger" also expanded Frog Lady's character design when she, Mando and Baby Yoda were being chased by giant spiders. Though she's bipedal most of the time, Frog Lady was able to put on a burst of speed by hopping on all fours. Sci-fi alien designs so often fall into the trap of just being humanoids with a bit of make-up and prosthetics, so introducing insectoid and amphibian characters like Dr. Mandible and Frog Lady gives The Mandalorian a wonderfully strange and unique world to explore.