Circle of the Beast

Circle of the beast druids forego their spellcasting ability to gain more access to wild shape options. As a Circle of the Beast druid you must study and record the creatures that you wish to become. These creatures come from the beast, monstrosity, and ooze lists. You use your spell slots to transform into creatures of equal or lesser CR value to the expended spell slot. 

Active Capture: While in your non shifted form, you must be able to physically see the creature that you wish to study, as an action you must make a WIS check to attempt to understand the creature, On 3 successful checks you record the creature and may add it to your roster, on 3 failed checks you are rendered unable to record the creature until you complete a short rest. During active capture you may make a perception check to lower the DC of the wisdom check.

Passive Capture: You may study a creature that is not in front of you  by means of reading a book, or hearing tales of the creature. You must make a WIS check to record the creature, while generally a higher DC, successful Investigation checks may lower the DC slightly. 3 successful attempts allows you to record the creature and add it to your roster, 3 failures renders you unable to record this creature until you complete a long rest.

Roster: You may only have up to 6 leveled creatures in your roster at a time. Cantrip level creatures do not count towards this total.

Beast Shift

The rites of your circle grant you the ability to transform into more dangerous beast forms. Starting at 2nd level, as an action you may use your spell slots to transform into a beast, monstrosity, or ooze of CR value equal to, or less than the spell slot expended.

Cantrip slots may be used to freely shift into a creature equal to 1/8 of your current druid level.

Cantrips may also be cast as regular spells

Leveled spells may only be cast as spells if granted by means other than druid levels.

Shifting Regeneration

When you choose this form at 2nd level, you gain the ability  to expend your wild shape slots to regain 1D8 HP per slot expended. This effect may only be used in your non beast form.

Beast Speak

At 3rd level, Once per long rest, while in your beast form, you may choose one other creature of the same type to speak with. For example beasts can speak with beasts, oozes with oozes, and Monstrosities with monstrosities. 

Primal Strike

Starting at 6th level, your attacks in beast form count as magical for the purpose of overcoming resistances and immunities.

Beast Shift Improvement

At 10th level, you can now shift into your beast forms as a Bonus Action

Savage Shifting

Beginning at the 14th level, you may now expend multiple spell slots  and combine their total worth to shift into a creature with equal or lesser CR value