ZiNi
ZiNi and its companion Human ZiNi (HZiNi) are measures of how many clicks a board is expected to take for a player who uses flags efficiently. They are analogous to 3BV, which measures how many clicks a board is expected to take for an efficient non-flagging player. The full details are described in this forum thread from 2009. It is unknown how large a ZiNi or HZiNi value can be; these are boards with the highest known values.
Beginner Board with 31 ZiNi
Beginner Board with 34 HZiNi
Intermediate Board with 111 ZiNi
Intermediate Board with 120 HZiNi
Expert Board with 239 ZiNi
Expert Board with 264 HZiNi
The definitions of ZiNi and HZiNi are usually pretty similar, with HZiNi being a bit larger because it simulates a more human-like (and thus less efficient) approach to the board. However, since they don't rely on each other and solve patterns in a different order, certain patterns can cause a very large difference between the two values. The "ZiNi Difference" here is HZiNi - ZiNi. Here are the boards with the highest and lowest known ZiNi difference.
Beginner Board with 11 ZiNi Difference (16 ZiNi, 27 HZiNi)
Beginner Board with -6 ZiNi Difference (25 ZiNi, 19 HZiNi)
Intermediate Board with 41 ZiNi Difference (46 ZiNi, 87 HZiNi)
Intermediate Board with -21 ZiNi Difference (76 ZiNi, 55 HZiNi)
Expert Board with 98 ZiNi Difference (89 ZiNi, 187 HZiNi)
Expert Board with -37 ZiNi Difference (216 ZiNi, 179 HZiNi)
Normally, ZiNi and HZiNi are much lower than 3BV, because using flags carefully lets a player save clicks. But certain patterns can make it nearly impossible to save clicks. ZiNi and HZiNi are defined in a way that they can never be greater than 3BV, but they can be equal to 3BV, which means the algorithm couldn't save any clicks over the non-flagging approach. These are the boards with the largest 3BV's where either ZiNi or HZiNi was the same number.
Beginner Board with 24 3BV and 24 ZiNi
Beginner Board with 28 3BV and 28 HZiNi
Intermediate Board with 83 3BV and 83 ZiNi
Intermediate Board with 93 3BV and 93 HZiNi
Expert Board with 165 3BV and 165 ZiNi
Expert Board with 207 3BV and 207 HZiNi