Techstacks i feel comfortable with, my tool belt so to speak.
I don't believe there is tool that fits all. But these are the ones i feel comfortable with. And i like to choose the tools that make me feel comfortable for any given task. I am not a fan of the 'best' tool, i am a fan of the tool that makes me feel comfortable.
Web Development
Laravel (PHP)
This stack provides fantastic developer experience and an unparalleled productivity working on web applications. Most notably in combination with the TALL-Stack. It can be scaled dramatically while being easy to maintain and offering a great dx.
Spring Boot (Java)
This can be a great choice for enterprise applications even more so if brownfield projects are involved.
Frontend Frameworks (JS)
I have extensive experience with Angular but prefer Vue.js for new projects. I have also worked with React.
Other languages i find myself using frequently
Python, Go, C++, C#
Infrastructure
Serverless
Having no servers to care about makes this a nice choice from an devops perspective, this can be a good fit in some cases. But care needs to be taken to keep it maintainable. This can be looked at from just an Devops perspective which is fine if the application is just hosted serverless but is itself a self contained monolith.
If the application is supposed to be a microservice architecture or cloud native, this is not just a Infrastructure / Devops topic but needs to be looked at from a software architecture perspective.AWS
One of its main advantages is the wide spread usage creating a vast community around it and a lot of help available. If configured through IaC the combination offers great maintainability.
Kubernetes
This is a mighty Sword and should be used with care. It is a great tool if it is needed but should not be used just because others use it too.
Design
Figma
I have started using Figma over Sketch lately, i am not a very good designer myself but i find most of the design community is using Figma - so this eases interaction with this community for me a lot.