I only know of one brand available new but there are unlocked refurbished ones available should you decide to go that route. I own 2 phones with removable battery. My carrier is t-Moble so both are GSM phones. Both were purchased within the last 6 months.
> LG V20 Released Oct 2016. Very rugged construction, titanium back (not plastic), very good hardware specs. GSM only as far as I know. Runs Android 7.0 (Nougat). No longer available new but refurbished ones are available.
> Motorola (now owned by Lenovo) Moto G4 Play (make sure it is the G4 *Play* - the Moto G4 does not have a removable battery). Released May 2016. According to my research the Moto G4 Play can be either CDMA or GSM. Moderate construction (plastic back - a little flimsy); moderate hardware specs. Mine came with Android 6 installed but Motorola pushed out a (free) Android kernel update this Spring so it now runs 7.11. You might be able to find this one new. This is a budget phone but still quite capable, especially with the kernel update.
Both phones have an internal microSD slot and a 3.5mm audio jack (both disappearing features in new phones).
Ownership Notes
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> LG V20 (refurbished & unlocked): owned for 1 month; cost: $205.
I got the AT&T branded one (LG model V20 H-910/H-910a); there is also a t-Mobile branded one (LG model V20 H-918) but I've had no problems using it on the t-Mobile network.
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Supports gaming and video well (processor can get a little hot with extended use). Came with a wide selection of pre-installed apps. Performs as well (or better) than phones 2x it's price. Should meet the needs of a fairly demanding user. A steal at $200. Highly recommended.
> Motoroloa Moto G4 Play (new & unlocked): owned for 6 months; cost: $100 but really requires a protective case which will bump up the cost a little.
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Does not support extended video viewing very well. Not for gaming. Fine for calls, messaging, browsing, light video. Came with a more limited selection of pre-installed apps than the LG V20 but they cover the basics. With only 2GB RAM this avoids the bloatware problem as pre-installed apps can only be disabled, not actually deleted (unless you root the phone). For a budget phone it delivers a lot. Good as an entry level phone for a user that doesn't need every bell and whistle and doesn't need/want to have a zillion apps.