All members of the Rescue Squad series' artwork feature their namesake animal wearing gear commonly associated with public safety workers, such as a whistle or a harness, and a hardhat. They are also always seen standing against a sky blue background, though it is often given a more white color due to the foiling of the card.
Ironically, the members of the Rescue Squad series aren't meant to work together. Rather, they are meant to facilitate the use of whatever new Summoning method Konami happens to be introducing at the time, as the mechanic is still in its early stages and still lacks support. To do this, they Summon monsters from the deck, which are destroyed during the End Phase.
After the original member, "Rescue Cat", who is often used with Synchro Summoning strategies, "Rescue Rabbit" was released early in the Yu-Gi-Oh! ZEXAL era to aid on Xyz Summoning; "Rescue Hamster" was released early in the Yu-Gi-Oh! ARC-V era to aid on Pendulum Summoning; and finally, "Rescue Ferret" was released early in the Yu-Gi-Oh! VRAINS era to aid on Link Summoning. In the latter, the Rescue Squad series also gained its first support card, "Emerging Emergency Rescute Rescue", meant to further speed-up the Summoning effects of the monsters by searching them more easily.