equivalent to select forward

I desperately hope after six years the people browbeating and clutching their pearls over AE being used to edit video have broadened their minds to both real world use-cases and to this specific ask. 

Firstly, while I would be the first to advise against using AE for video editing, there are scenarios in which bringing video into the app, sometimes with edits, is unavoidable and necessary. Yes, you could make the cuts in Premiere and export and then bring that file into AE but let’s call a spade a spade: that is an absolute pain to commit to, especially with frequent changes to footage. Ergo there is a real reason to seek ways to make video editing a bit easier in AE, if only as an occasional, necessary evil.

Second, OP’s question is absolutely sound and logical and no response here actually spoke to the nature of the ask: while their timeline formats and use cases are very different from one another, both AE and Premiere deal with layers sequenced in time, with start points and end points on the timeline, be it shape layers, pngs, video, whatever: every layer has a point at which is starts and a point at which it ends. The ability to rapidly jump forward and backward on the timeline based on layer in/out data is extremely useful in many scenarios. No, it doesn’t replace pre-comps or color-coding or any of the time-honored AE best practices, but that simple functionality would go a long way in simply navigating via keyboard. Maybe there is a way to do this with shortcuts.

Broadening to general video editing use in AE, folks like Jake Bartlett have designed plugins (admittedly vibe-coded, make of that what you will) that effectively provide an interface that is more intelligible for simple, NLE-like editing, even if under the hood AE is dealing with video the same way it always has. As other suggested, pre-comping an edited video layer is another way to quickly clean up the timeline, and scene-edit-detection can generate markers (other plugins too I’m sure) that will display edits as markers in the timeline so they can be referenced wherever that pre-comp lives.

I know a certain generation of industry AE people (and editors!) are especially nasty and gate-keeping with questions like this, but as a general reminder, even all this time later: it costs nothing to be patient and kind, and could mean the world to someone struggling with learning the ins and outs,  and still learning the best practices of time-based media software. Something being self-evident is rarely the case if experience is stripped away. All we have is each other: better to lift someone up than to put them down.

AE doesn't provide an auto feature to select layers forward or back in time relative to a distinct point in time. You can do so with KF selections (right-click on a KF to prompt a pop-up menu and commit to appropriate selection) but not layers.

Other than precomposing to reduce the number of layers within a comp, you will want to look at grouping layers based on their Label Colors, in the Timeline. You can create a shortcut to select layers with the same Label Color as well as shortcuts to create/apply Label Colors to selected layer(s). The Keyboard Shortcuts Visualizer (KSV) is where you create these shortcuts. In the KSV, search for Label to quickly view the Commands related to Label Colors. Then, create the shortcuts for these Commands.

You can also select (first layer) and then add SHIFT when clicking on the another layer, to select a contiguous group of layers. For non-contiguous layer selections, use the CTRL key while selecting additional/subsequent layers, after having selected the initial layer.
HTH

You need to use Precompositions in Ae, this is one of the best way you have to group your Layers making easy select it. Obviously the way to work it's different.