Although Trump criticizes the WTO, his administration has nevertheless initiated case there, for example 5 cases against retaliatory tariffs last year:
[07/16/2018:] The Trump administration on Monday formally challenged tariffs imposed by China, the European Union, Canada, Mexico and Turkey on more than $20 billion of U.S. exports in retaliation for steel and aluminum duties imposed by President Donald Trump in the name of national security.
The five cases go after duties imposed by China on $3 billion of U.S. exports; the EU on $3.2 billion; Turkey on $1.8 billion; Canada on $12.7 billion; and Mexico on $3.6 billion.
The United States asked each of the five trading partners for consultations under the World Trade Organization's dispute settlement procedures. [...]
“Instead of working with us to address a common problem, some of our trading partners have elected to respond with retaliatory tariffs designed to punish American workers, farmers and companies,” U.S. Trade Representative Robert Lighthizer said in a statement.
“These tariffs appear to breach each WTO member’s commitments under the WTO Agreement. The United States will take all necessary actions to protect our interests, and we urge our trading partners to work constructively with us on the problems created by massive and persistent excess capacity in the steel and aluminum sectors,” he added.
Of course countries affected by the US aluminium tariffs were not idle either, having launched 8 cases against the US at the WTO (not all imposed retaliatory tariffs).
Are these the only examples of WTO cases launched by Trump administration? (If not, how many more are there?) Also, are there some statistics that plot/compare the number of cases launched by the US e.g. per year, so we could compare with previous administrations?
N.B. I was able to find that the Obama administration had launched at least 25 cases at the WTO, 16 against China. That's basically for the whole 8 years of the Obama presidency, more precisely until January 12, 2017. (So it was approximately 3.13 cases/year.)