Volunteering

European Voluntary Service (also known as EVS) is an international volunteer initiative that lets you carry out voluntary service in a project and country (mostly in Europe) of your choice, with a duration of up to 12 months. It is funded by the European Commission and it is for people between 18 and 30 years old, who are legal residents in the country of the Sending Organization (more on that soon).
There is no cost associated, and it covers costs with travel, accommodation, travel insurance, pocket money, and language course.
The projects focus on various themes, from teaching ESL to post-disaster humanitarian aid, helping out in a youth center, homeless organization, or animal shelter. You can consult the list of projects here.
To do EVS, you will also contact a Sending Organization, from your country of residency, that does the volunteers' deployment and management. Google the expression "EVS sending organization [your country]" to find them easily.
It can be an incredible opportunity to develop skills of citizenship and solidarity, to experience life in a different country from yours, and to and make friends for life who will have shared an amazing experience with you! Check this and this guide for more details.

Moving Worlds is a platform that matches volunteers with organizations around the world to help under-resourced communities and contribute to the greater good.
There are three types of what they call Experteering projects: you can train an organization on a skill (ex: using Excel, marketing analysis, etc.), support a team on completing a specific task, or be a strategic consultant. The projects range from topics as accounting to architecture, business, HR, data science, web development, and many more.
This is a paid program. Yearly access to the platform, to join the community, and apply to opportunities is $250, but after that, you don't have to pay the receiving organization and sometimes they provide you with accommodation and meals or a living stipend.
For a $3,600 tuition, you can access the Fellowship program, including a volunteering project, coaching, career guidance, and leadership skills development (if you work, you can try to get your company to support these fees).

Grassroots Volunteering has a database of volunteering opportunities all over the world, focused on empowering travelers to connect to causes and communities in their destinations. They have two different databases: Volunteer Opportunities with independent community-based volunteer organizations, and Social Enterprises, small businesses with an underlying social mission. Most opportunities are free of charge (meaning you don't have to pay the organization anything to volunteer there), but some have a small fee associated.

Omprakash is a global network of volunteers and partner organizations, where impactful organizations can showcase their work and receive candidates' applications to volunteer with them. Their search is very efficiently organized by location and area of work. Due to Covid-19, many organizations have available opportunities for online work, and the website allows you to directly search for the type of Online work you'd like to do. The website is also a network platform to connect with other volunteers and learn about their work and interests.

Idealist is a nonprofit organization that lists volunteer, job, and internship opportunities. These are constantly being updated, and it is possible to find a wide variety of work focus and locations. The search is organized by location, including choosing remote-only, issue areas, and needed skills.
They also have valuable resources, from Career and Grad School advice to Ideas for Action, a collection of inspiring articles that will prompt you to do good.

All Hands and Hearts is a disaster-relief organization powered by volunteers. Their programs help the communities affected by natural disasters. They have programs in North, Central, and South America, Australia, Nepal, and Southeast Asia - some of their programs are temporarily suspended due to Covid-19, but the ones remaining have been redesigned to minimize the virus's impacts.
The programs cover expenses with flights and local travel, accommodation, small stipends, meals, and medical expenses. The volunteers also receive training on subjects that include technical, humanitarian, diversity, team building, ethical storytelling, and first aid, receiving a certificate upon completion.

Entremundos is a nonprofit organization from Guatemala focused on fighting against poverty and promoting Human rights in this country. Their actions include a) conducting a Capacity Building Program that includes IT courses and other workshops to provide locals with skills and tools to improve their performance individually and institutionally; b) the Volunteer program and c) their magazine. Through the volunteer program EntreMundos places volunteers within over 100 local organizations, depending on skills, interests, time commitment, experience, and Spanish language level.
It's also possible to volunteer for the organization itself. The activities may include research support, translation, workshop advertising, admin, social media development, fundraising, and guest house management. Check this document for more information on the program.

WWOOF stands for World Wide Opportunities on Organic Farms. This platform promotes a worldwide organic farming movement and creates a link between farm hosts, helpers, and visitors who wish to learn further and experience rural living. You can participate in helping on the farm, doing a myriad of stuff that can range from collecting wood to planting vegetables, assisting with cleaning, or taking care of animals (check each host for the job's specificities). You will also be learning about sustainability, experiencing a new culture, and meeting new people. You will receive free housing during your stay. To start this experience, you must first pick the country where you would like to join. Then, you can sign up to find a host.