I once read something about how the second hokage had a daughter that married a namikaze and minato being the grandson or great grandson of tobirama.
It was in some jap mag, leaked info, fiction or dunno what precisely anymore.
True or not, i thought it sounded kewl.
Their techniques are simlar.
They both are able to sense enemies by touching the ground with their finger and they both use spacetimejutsus without sharingan.
Similar hairstyle and attitude.
In the anime, for as far as that counts, the second hokage had a sword called sword of the thundergod. So they even both use this thundergod name for their jutsu.