Namechk is a great OSINT tool that allows you to find out if a username you are investigating is used elsewhere online.  It includes various social media platforms as well as domain names and mobile apps.  Typically an investigation starts with a name, phone number, or email address.  If you don't have any of the above, you can start with their username.  People often use the same user name on multiple platforms and some platforms automatically import the username from your email by default. Having a username to start isn't ideal, but Namechk allows you to explore the information you have to try to find other information.

MyMaps by Google is a bare-bones GIS app that allows you to create custom maps for projects you are working on.  I like it because I can quickly plot markers for locations of interest in an area I’m investigating and reference them when collecting information that is geotagged. It also allows you to create different layers to organize the markers based on type. It has limitations, such as the amount of markers you can put in each layer and the lack of support for Google Street View within the app.

Feedreader is a browser based RSS reader. What I like about it is you can create separate categories for different types of feeds, allowing you to monitor and organize different types of information.  You can create RSS feeds out of Google Alerts, Google News, and other types of aggregators.  This will allow you to automate a lot of your news collection tasks. 

If you're an OSINT investigator or use OSINT in any of your work, it's impossible to ignore Twitter as a collection source.  With data privacy concerns being a hot topic, many other social networks are cracking down on their API, making it harder for people to collect OSINT on social platforms.  Twitter remains my go-to for investigations on social media.  I use TweetDeck, a dashboard that allows you to view Tweet streams based on parameters you select such as user names, hashtags, keywords, and a variety of other built in features.