Moto uses the default option for viewing pictures or videos on Android: Google Photos. Gallery functionality isn't as intuitive as other custom galleries, but there are plenty of features and functionalities for Google Photos.
Just keep in mind, many of these features require you to upload all of your photos to Google's photo cloud. You can search photos by person or keyword, and Google Photos can even automatically generate collages, GIFs, and short video montages.
If you opt out of Google's cloud service, you can still manage albums and edit photos.
There are plenty of editing tools as well. What you won't find in Google Photos is a way to scribble on photos or inserting stickers. But you will be able to use filters, basic crop and rotation, and light/color correction with levels.
Video playback is nothing more than bare bones. You can seek with a progress bar, toggle loop playback, or share the video. You can also edit videos taken with the phone, though it's only a very basic trimming tool. Otherwise, there's no support for subtitles, swipe-to-seek, or playback speed adjustment.
Moto uses the Android-default option for music playback. Google Play Music offers a vast collection of music that you can listen to for free with supporting ads, or you can upload up to 50,000 tracks from your own MP3 collection that you can stream anywhere you go. You can even save these tracks offline with the free version.
You can opt for a subscription that includes all of the features above with no ads and unlimited skips. YouTube Red comes bundled with the subscription, too, and it allows for watching YouTube videos offline, screen-off playback, and an ad-free viewing experience.
Google Play Music is very contextual and can recommend music for you based on your location. It learns what you listen to, and at what times to offer suggestions for stations or playlists.
Google Music's navigation is arguably cumbersome. You have a hamburger menu with several options. Google's Music App can also play back locally store music. You can browse by playlist, stations, artists, albums, songs, and genres.
Google Music also has a collection of podcasts, which you can still use with the free version. The curated radio stations are powered by Songza and is quite diverse. You can find a radio station for any occasion, activity, mood, or decade.
Gboard is the default keyboard from Google and offers many features, predictive text, simultaneous language support, emoji and GIF search, and perform Google searches directly from the keyboard. To look something up or share a result.
For what it's worth, there's an ongoing startup campaign for the "Keyboard Mod": a slide-out QWERTY keyboard that can be slapped onto the Moto Z2 Force (or any Moto Z model).
While this technically means you can use a hardware keyboard on a 2017 top-tier device, keep in mind it's from a third-party accessory maker. Samsung has offered a physical keyboard accessory on the Note7 and the Galaxy S8, but these solutions aren't arranged in a more comfortable landscape orientation and take up screen space.