The Riven build for Top is Eclipse and Conqueror. This LoL Riven guide for Top at Platinum+ on 13.24 includes runes, items, skill order, and counters.
Riven Counters
50.7%
(+0.6%)
47.0%
(+0.3%)
4.1%
(+0.5%)
1.2%
(+0.2%)
685
(+1)