Best card to use the hero power on early game is Strike Oil, if you get it on turns 3 or 4. You then basically pay 2 gold for 1 gold every turn for the rest of the game, it's a great deal. Later on I like using the hero power on 5 or 6 drop spells since those are usually the most expensive and high in power! Examples range from Eyes of the Earthmother to Golden Touch or even Boundless Potential.
minder
Don't get baited into early heropowers with little effect. Look for high impact spells and focus on duplicating them but don't base your whole game around it
Placement Distribution
0.2%
#1
0.1%
#2
0.2%
#3
0.1%
#4
0.1%
#5
0.1%
#6
0.1%
#7
0.1%
#8
Warband Strength
1
2
11
3
22
4
33
5
55
6
93
7
160
8
317
9
592
10
1046
11
1798
12
2841
13
4530
14
6025
15
6255
16
Combat Winrate
33%
1
21%
2
38%
3
41%
4
46%
5
44%
6
46%
7
48%
8
50%
9
52%
10
50%
11
50%
12
51%
13
57%
14
57%
15
62%
16
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