Which is the strongest base? When I was in lower grades, I was taught $\ce{NaOH and KOH}$ are the strongest bases. But I realised later that there can be more stronger ones. After a bit of research on the internet, I found these three to be spoken more about.


Lithium diisopropylamide (LDA)
Methyllithium (MeLi)
Butyllithium (BuLi)


Wikipedia on LDA says that the $\mathrm{p}K_\mathrm{a}$ of its conjugate acid is $36$, which means the $\mathrm{p}K_\mathrm{b}$ value at $\pu{298K}$ is $-22$. (Since $\mathrm{p}K_\mathrm{a} + \mathrm{p}K_\mathrm{b} = 14$).
Likewise, for BuLi and MeLi I found the $\mathrm{p}K_\mathrm{b}$ value to be $-36$ and $-34$ respectively from the $\mathrm{p}K_\mathrm{a}$ values of their conjugate acids. So, can we conclude that BuLi is the strongest base? Is this absolute basic strength defined? 



Sources for $\mathrm{p}K_\mathrm{a}$ values:


Wikipedia-LDA
pKa of MeLi and BuLi
Looks like it's neither of the three; ortho-diethynylbenzene dianion has the highest calculated proton affinity.  

From Wikipedia


  


according to calculations, ortho-diethynylbenzene dianion is the strongest base, with a proton affinity of $\pu{1843 kJ \cdot mol^{−1}}$.  

This base claimed the title of the strongest base 2016 ish, another base may have grabbed the spot but I haven't been able to find it.

B L J Poad et al, Chem. Sci., 2016, DOI: 10.1039/c6sc01726f