So, since a bit of time has passed, with the pandemic and all that, I wanted to see what's the state of the SBC world, if the known manufacturers are still there and what are they up to now.
I'll try to see if they still make Allwinner H3 based boards, what's their Raspberry Pi contender (and what chipset it uses) and what's their Raspberry Pi Zero alternative (and chipset).
Orange Pi (Shenzhen Xunlong)
Orange Pi H3 offering included the Lite, PC, PC Plus, One and Zero.
All seem to be still available on AliExpress with prices from $25 to $45.
Their current RPi contender seems to be the Orange Pi 3B, that uses a Rockchip RK3566.
Their RPi Zero contender is the Orange Pi Zero 2W with an AllWinner H618.
Banana Pi (Guangdong Bipai Technology)
Banana Pi H3 offering includes the BPI-M2 Zero (their RPi Zero contender), BPI-M2+ and BPI-P2 Zero.
You can get a BPI-M2 Zero for around $20-30 on AliExpress.
They have 2 RPi contenders:
BPI-M4 with Realtek RT1395 and BPI-M4 Berry with Allwinner H618.
NanoPi (Friendly Elec)
Their H3 offer are the M1 Plus, that goes for $45-60 on AliExpress and the Duo2 (their "Zero") for around $30-40.
Their RPi contender is the M4, with a Rockchip RK3399.
They have the ALL-H3-CC (Tritium) boards. But their H2+/H3 boards (under $20) seem to be out of stock.
Their RPi contenders are the AML-S905X-CC (Le Potato) with Amlogic S905X and the ROC-RK3328-CC (Renegade) with Rockchip RK3328.
And of course, the mother of all SBCs, Raspberry Pi 5, just released with an Broadcom BCM2712 chip and a custom controller.
And other than that, there's the HTPC set top boxes with H3 chips inside.
If you find another board worth mentioning, just put it here.
I hope you find the information useful.
Edit: while Mango Pi has no H3 offering, they have a Zero style board, the MQ-Quad, with H616 and H618 chipsets.