Salesforce Advanced Search plugin works in both Classic and Lightning:
i) Search any keyword, text or field api name used anywhere in below Salesforce Components, in the result section plugin shows the total number of files where keyword has been used in different components. Plugin also provides to choose which all components to search in for the keyword via checkbox selection:
1) Apex Classes
2) Apex Triggers
3) Visualforce Pages
4) Visualforce Components
5) Email Templates
ii) Show Field API Names with Labels of an object in details page, you can toggle between Show and Hide Field API Names without refreshing the page.
It's also available for Chrome:
https://chrome.google.com/webstore/detail/salesforce-advanced-searc/lbkpckaekpilejfambbkphfedniacanj
