Sometimes, counterfeits or unknown brands are so similar to the real deal that it barely matters. I'd say that basic electronics (alarm clocks, kitchen scales, calculators, SD security cams) or even RAM is fine. With appropriate expectations, parts like video or USB cables, hubs etc., small home improvement items (hooks, screws) are fine too. Avoid categories where a lot of items have fake specs (storage devices, LED bulbs, anything that claims a runtime on a Li-Ion battery). Power electronics (especially if using mains or non-tiny Li-Ion batteries) can be downright dangerous. For novelty items and electronics modules, it's usually easy to find text or video reviews on other websites because they're easy to uniquely describe. Remember to consider ways in which the product can be utter crap despite high reviews citing good first impressions; it also helps to have practical knowledge of testing the properties of the items and fixing common issues.