Training Multiple Models in Google Colab
The amount of usable GPU and RAM on Colab is limited on Colab. You can try out how many scripts you can run at the same time and could start using other accounts after that. Note that inactive sessions in Colab will be closed.
I personally would try to find a way involving less computational power. Google Colab has got a limited amount of hardware available, and using it too much might result in other users not being able to use a GPU. Also, abusing its capacities could result in a ban for you.
I am building an ensemble of models and need to do hyperparameter selection on 126 different models ranging from linear models to keras model with each taking 4-18 hours to run.
I plan to do that on google colab as i do not have enough computing resources. 
Should i open 126 google accounts and train all of the models in parallel using 126 colab CPUs / GPUs. Or should i open 126 colab notebooks on the same account and run the models there. Will the 126 notebooks share the same resources or will each notebook have access to separate CPUs.