Separate high value rider policy on home insurance. This will provide actual physical value security and must be updated yearly.

Same process if you only rent. Normally covers everything BUT flooding. Talk with your agent.

Expect to do required additional legwork on appraisals, photos, serial numbers, and proof of ownership. You may require references. Do not use "antique shops" as they are worthless. Baseline game values can be acquire from the Mr Pinball Price Guide 2017 with adjustments made for game condition, unless the games were made before 1945. Make updates as needed. If "third party" values are required seek out a reputable used game dealer. New game distributors are not always optimal.

I have had games separately insured since 1990 as a requirement of a large volume collection.

If an owner wants to ensure protection of a game's full market value (and must be periodically updated), do not "lump" it under your home owner's or renter policy. This is a bad choice.

It is no different than any other high end collectible, especially when it comes to a high volume collection of high quality exceeding more than $250K or more. Separate insurance is a necessity. A person is free is disagree, but I have been on the supporting end of appraisals to insurance companies regarding these situations. I don't know too many insurance agents that are qualified to provide experience on pinball appraising in order to end of supporting a correct reimbursement. It is that old "subjective" aspect.

If a person owns a handful of games, it really is not significant, no rider required, use existing homeowners or renter's policies.
Still take good photos and record those serial numbers!