Several 2018 Top @prospects Lists here for reference:
MLB Pipeline: http://m.mlb.com/prospects/2018?list=prospects
Baseball America: https://www.baseballamerica.com/minors/top-100-mlb-prospects-2018/#0iA6SSeh1wrH4tv4.97
Baseball America (Top 10 by Team): https://www.baseballamerica.com/minors/2018-mlb-top-10-prospects/
Baseball Prospectus: https://www.baseballprospectus.com/prospects/article/37535/baseball-prospectus-top-101-prospects-2018-top-mlb-prospects-ronald-acuna-victor-robles-vladimir-guerrero-jr-eloy-jimenez/
Baseball Prospectus (Top 10 by Team): https://www.baseballprospectus.com/prospects/
FanGraphs: https://www.fangraphs.com/blogs/2018-top-100-prospects/
FanGraphs (Fantasy Spin): https://www.fangraphs.com/fantasy/2018-top-100-prospects-fantasy-spin/
RotoGraphs: https://www.fangraphs.com/fantasy/2018-top-100-fantasy-prospects-first-look/
KATOH: https://www.fangraphs.com/blogs/2018-top-100-katoh-prospects/
Minor League Ball (by Team): https://www.minorleagueball.com/2017/10/24/16485986/top-20-prospects-lists-mlb-2018-index-by-organization
Prospect 361: https://prospect361.com/prospects/2018-top-100-prospects/
ESPN (Keith Law): http://www.espn.com/mlb/insider/story/_/id/22200858/keith-law-top-prospects-2018
Clubhouse Corner (Top 32): http://clubhousecorner.com/2017/12/15/top-32-mlb-prospects-2018/
Dynasty Guru: https://thedynastyguru.com/2017-tdg-consensus-dynasty-league-rankings/
Prospects1500 (by Team): http://prospects1500.com/top-50-lists-2018/
Big3Sports: https://www.bigthreesports.com/top-100-prospects-mlb-2018/
Razzball: https://razzball.com/top-100-prospects-for-2018-fantasy-baseball/
Feel free to add others you find.