So far, AMD has only officially announced three Navi models, the Radeon RX 5700 XT and Radeon RX 5700, along with a 50th Anniversary Edition of the former. It's a safe bet there will be additional models, though, and perhaps soon, based on a breakdown of a recent Linux display driver update.
Twitter user and frequent hardware leaker APISAK called attention to the updated driver code. The original reference has since been taken offline, though not before a screenshot was grabbed.
NV_NAVI10_P_A0 = 1,NV_NAVI12_P_A0 = 10,NV_NAVI14_M_A0 = 20,NV_NAVI21_P_A0 = 40,NV_NAVI10_LITE_P_A0 = 0x80,NV_NAVI10_LITE_P_B0 = 0x81,NV_NAVI12_LITE_P_A0 = 0x82,NV_NAVI21_LITE_P_A0 = 0x90,NV_UNKNOWN = 0xFFhttps://t.co/gUMCpbtAcZJune 18, 2019
The Radeon RX 5700 XT (including the 50th Anniversary Edition) and 5700 are both based on Navi 10, the latter of which is potentially referenced as "Navi 10 Lite" in the Linux driver. But there are also references to Navi 12, Navi 14, and Navi 21 (regular and Lite).
It's not clear what exactly those are, because AMD has not yet announced any other models. However, it hints at a more fleshed out Navi stack to go up against Nvidia's growing lineup of Turing cards.
As The Inquirer notes, they may not even necessarily reference consumer desktop cards—they could be workstation or even mobile GPUs. It's really just a guessing game, at least for now.
That said, we're fairly certain that more Navi cards are on the horizon. It would be highly unusual for AMD to only launch the 5700 series and call it a day. AMD is aggressively shifting to 7nm parts, and the only other consumer GPU on 7nm right now is the Radeon VII, based on Vega.
Everything we know about the Radeon RX 5700 XT right now suggests it will compete against Nvidia's GeForce RTX 2070, and while the 5700 will go up against the RTX 2060. That leaves the field wide open for more Navi cards. We'll have to wait and see what exactly materializes.