I've been in progressives that had these rules to mitigate the impact of tanking: (1) The draft order is set based on the standings after 120 games; (2) A team must have at least 30 wins after 120 games in order to have a chance at the #1 draft pick. For every win below 30, that team's best pick would fall one spot. However, the worst pick that the team with the worst record could have in this scenario was #5 overall; (3) Institute a lottery among the four worst teams for the #1 overall pick; (4) The previous three rules apply to the first round only. Draft order in all other rounds is based on the reverse order of won-loss record after 120 games.
There's no perfect way to combat tanking. But, I found that these rules force teams to be at least somewhat competitive.