Here's a list of 100 free tools to help you with various aspects of digital marketing:

Search Engine Optimization (SEO):

1. Google Keyword Planner: For keyword research.
2. Google Analytics: To track website traffic.
3. Google Search Console: To monitor your site's presence in Google search results.
4. Google PageSpeed Insights: To check and improve website loading speed.
5. MozBar: For on-page SEO insights.
6. Yoast SEO: A WordPress plugin for SEO optimization.
7. Screaming Frog SEO Spider: For website crawling and analysis.
8. Ubersuggest: Keyword research and competitor analysis.
9. SEMrush: Offers a free version with limited features.
10. Ahrefs Backlink Checker: To analyze backlinks.
11. AnswerThePublic: Generates content ideas based on questions people ask.
12. Keyword Surfer: Chrome extension for keyword research.
13. GTmetrix: Website speed and performance analysis.

Content Creation and Marketing:

1. Canva: For creating visual content.
2. Grammarly: To check and improve your writing.
3. BuzzSumo: To discover popular content.
4. Hootsuite: Social media management tool with a free plan.
5. Buffer: Another social media scheduling tool with a free plan.
6. Mailchimp: For email marketing (free for small lists).
7. Trello: Organize and manage content projects.
8. Asana: Task and project management tool.
9. HubSpot Blog Ideas Generator: For content brainstorming.
10. Piktochart: Infographic maker.
11. Crello: Graphic design tool for social media.
12. Headline Analyzer by CoSchedule: Helps you create engaging headlines.
13. Portent's Content Idea Generator: Generates creative content ideas.

Social Media Marketing:

1. Facebook Business Suite: Manage your Facebook and Instagram accounts.
2. Twitter Analytics: Insights on your Twitter performance.
3. LinkedIn Page Analytics: Monitor LinkedIn page performance.
4. Pinterest Analytics: For Pinterest business accounts.
5. Instagram Insights: Data on your Instagram content.
6. Later: Visual content scheduler for Instagram.
7. TweetDeck: Twitter management tool.
8. SocialBee: Social media posting scheduler.
9. Zapier: Automate social media tasks.
10. Canva Video Maker: Create animated social media videos.

Email Marketing:

1. MailerLite: Free email marketing platform.
2. SendinBlue: Offers a free plan with email and SMS marketing.
3. Benchmark Email: Free email marketing for small lists.
4. MailerSend: Transactional email service with a free plan.
5. Mailjet: Email marketing platform with a free tier.
6. Moosend: Email marketing with automation capabilities.
7. Omnisend: Marketing automation for e-commerce businesses.
8. Sender: Email marketing tool with a free plan.
9. SendPulse: Offers a free plan for email marketing and more.
10. EmailOctopus: Simple email marketing with a free plan.

Analytics and Data Visualization:

1. Google Data Studio: Create interactive reports and dashboards.
2. Tableau Public: Data visualization tool.
3. Infogram: Create infographics and data visualizations.
4. Power BI: Business analytics tool by Microsoft.
5. Databox: Business analytics dashboard with a free plan.

Video Marketing:

1. YouTube Studio: Manage and analyze YouTube videos.
2. Clipchamp: Online video editor.
3. Lumen5: Video creation from text and articles.
4. InVideo: Online video editor with a free plan.
5. Powtoon: Create animated videos.

Paid Advertising:

1. Google Ads: Advertising platform with a budget limit.
2. Facebook Ads Manager: Create and manage Facebook and Instagram ads.
3. Bing Ads: Microsoft's advertising platform.
4. LinkedIn Ads: Advertising on LinkedIn.

Social Media Graphics:

1. Adobe Spark: Graphic design tool.
2. Snappa: Graphic design software with a free plan.
3. FotoJet: Online graphic design tool.
4. Fotor: Photo editor and graphic design tool.
5. Pixlr: Online photo editor.

Content Management and Website Building:

1. WordPress: Popular CMS (content management system).
2. Wix: Website builder with a free plan.
3. Weebly: Website builder.
4. Blogger: Free blogging platform by Google.
5. Tumblr: Microblogging and social platform.
6. Medium: Blogging and publishing platform.

Social Media Listening and Monitoring:

1. Google Alerts: Monitor mentions of your brand.
2. Hootsuite Insights: Social media listening tool.
3. Social Mention: Real-time social media search and analysis.
4. TweetReach: Twitter analytics tool.
5. Brandwatch: Offers a free trial for social listening.

Project Management and Collaboration:

1. Toggl: Time tracking and project management.
2. Notion: All-in-one workspace for team collaboration.
3. Zoho Projects: Project management software with a free plan.
4. ClickUp: Project management and productivity tool.
5. Monday.com: Work operating system with a free trial.

E-commerce and Online Store Tools:

1. Shopify: Offers a free trial for building an online store.
2. WooCommerce: E-commerce plugin for WordPress.
3. Big Cartel: Online store builder with a free plan.
4. Ecwid: E-commerce solution with a free tier.
5. OpenCart: Open-source e-commerce platform.

SEO and Website Audit:

1. Google PageSpeed Insights: For website speed analysis.
2. Google Trends: Monitor search trends.
3. Google Analytics: Track website traffic.
4. Ubersuggest: Keyword research and SEO analysis.
5. SEOquake: SEO audit and analysis tool.

CRM (Customer Relationship Management):

1. HubSpot CRM: Free CRM software with marketing and sales tools.
2. Zoho CRM: Offers a free plan for basic CRM features.
3. Freshsales CRM: CRM tool with a free plan.
4. Bitrix24: CRM with collaboration and communication tools.

Survey and Feedback Tools:

1. SurveyMonkey: Online survey tool with a free plan.
2. Typeform: Create interactive and engaging surveys.
3. Google Forms: Free online forms and surveys.
4. Qualtrics: Offers a free plan for basic surveys.
5. Cognito Forms: Online form builder with a free plan.

These tools cover a wide range of digital marketing needs. Remember to choose the ones that align with your specific goals and strategies.