Along with the new Shield TV and TV Pro, Nvidia introduced a brand new remote for its set-top boxes. It has a triangular profile, plenty of buttons, and shouldn't be easily lost thanks to its built-in locator. But in case you did manage to lose it or you want an extra one to secretly control the TV when your partner or kids think they have the remote, you should be able to buy it in January 2020 for $30.
Compared to the old remote, the new one adds a power key, a user-programmable multipurpose button, fast-forward, play/pause, rewind, proper volume controls, and a dedicated Netflix button that can be re-purposed. It also has IR to control your TV and that aforementioned lost remote locator feature.
The new remote should soon also be compatible with the previous Shield TVs (2015 and 2017), according to 9to5Google, which explains why it's currently the only remote listed on Nvidia's online store. But you'll need to wait two months to order it, as it won't be available before the end of January 2020.