There is no specs in eso like other games, ardent flame, draconic power, and earthen heart are class skills that you can combine and slot from the 3 lines, however what you can call specs are dependent on the main resources, stamina dk uses stamina/weapon power/weapon critical ...etc, magica dk uses magica/spell power/spell critical ...etc.

Most class skill lines abilities and passive scale with magica, since stamina have 4 weapon skill lines while magica 2.

For stamina dk for example you have venemous claw, noxious breath, flames of oblivion, standard of might, corrosive armor and some other utility abilities you can use depending on experience and instance.

Keep in mind that all ultimates scale with your higher stats, it is just better to use the physical/poison/desease ulti since they scale with cp for stamina, same for magica with flame/frost/shock and magic.

There is sites like tamriel foundary, alcasthq, deltiasgaming that can give you ideas and builds.