[level 2 forms]
These are the first forms available to a Druid of the Land. While the restrictions cover Fly and Swim speeds, they do not ban climb or burrow speeds.
Horse, Camel, Cat, Rat, Toad, Lizard- these aren't combat forms, obviously. These forms are for sneaking about in a city or outpost. Just don't get hit or you revert.
Swarm of Rats- There's currently a beautiful loophole. There's nothing to say that your character can't wildshape into a swarm. Swarms get resistance to physical damage types, respectable attacks, and a nice thematic element of a wild man embodying the fury of nature bursting into its smallest, angriest components. This is your earliest swarm.
[level 4 forms]
CR 1/2 and a Swim Speed. Depending on the campaign, this can be a great or sub-par unlock. At the moment, I'm in a campaign taking place in a desert, so Swim forms aren't exactly topping my interests here.
[level 8 forms]
CR 1 and a fly speed. This is where a Land druid's wildshaping stops improving. For Land druids, this is when the Insect swarms come online. , climb speeds, and an attack that does a respectable 4d4 damage.
Swarms of Insects:
Resistance to physical damage, climb speeds, and an attack that does a respectable 4d4 damage.
Swarm of Bees: Insert image of Nic Cage. Bees/hornets are nothing to laugh at with a fly speed of 30.
Swarm of Beetles: Scarabs! Stag Beetles! Goliath Beetles! Ladybugs! Whatever is most thematically appropriate for your character, this swarm gets the best utility speed of all: Burrowing. Dungeon walls and floors mean NOTHING before the onslaught of a wave of angry beetles.