This is a curated list about tools for everything from productivity to hosting to development tools to designing. These tools are all digital i.e. either app, online service, or downloadable software. Most of them are either free or have limited free option that is enough for startups. Feel free to suggest and contribute in this list.
GitHub - https://github.com
BitBucket - https://bitbucket.com
GitLab - https://gitlab.com
GitHub pages - https://pages.github.com/
Amazon AWS - https://aws.amazon.com
Microsoft Azure - https://azure.microsoft.com
Google Cloud - https://cloud.google.com/
Heroku - https://www.heroku.com/
OpenShift by Red Hat www.openshift.com
AppFog - https://console.appfog.com
BlueHost - https://www.bluehost.com/
DreamHost - https://www.dreamhost.com/
Pagodabox https://pagodabox.com/
Surge - http://surge.sh/
Netlify - https://www.netlify.com/ Hi Adele
CloudFlare - https://www.cloudflare.com/
ClouDNS - https://cloudns.net/
Let's Encrypt - https://letsencrypt.org/
Pingdom http://tools.pingdom.com/fpt pingdom.com - Website monitor
Google Page Insight https://developers.google.com/speed/pagespeed/insights
Web Page Performance Test - http://www.webpagetest.org/
GTMetrix http://gtmetrix.com/
Import.io - https://www.import.io/
Web Hose - https://webhose.io/scraping-tools
Dexi.io - https://dexi.io/
Parse Hub - https://www.parsehub.com/
80Legs - http://80legs.com/
Scraping Hub - https://scrapinghub.com/
Scrapy - https://scrapy.org/
Scraper - https://chrome.google.com/webstore/detail/scraper/mbigbapnjcgaffohmbkdlecaccepngjd/related
Web Scraper - https://chrome.google.com/webstore/detail/web-scraper/jnhgnonknehpejjnehehllkliplmbmhn
Sublime Text - https://www.sublimetext.com/
Microsoft Visual Studio Code - https://code.visualstudio.com/
Microsoft Visual Studio (IDE) - https://www.visualstudio.com/
Atom - https://atom.io/
PHPStorm - https://www.jetbrains.com/phpstorm/
WebStorm - https://www.jetbrains.com/webstorm/
NetBeans PHP - http://netbeans.org/
Eclipse - https://eclipse.org/
CodeAnywhere - https://codeanywhere.com
Cloud9 - https://c9.io
Koding - https://koding.com
JSFiddle - https://jsfiddle.net
Plunker - https://plnkr.co/
CodePen - http://codepen.io/
JSBin - https://jsbin.com/
FileZilla - https://filezilla-project.org/
Laragon - https://laragon.org/
XAMPP - https://www.apachefriends.org
WinScp - https://winscp.net
Putty - http://www.putty.org/
Code Climate - https://codeclimate.com
JSLint - Usually available as plugin for IDEs/Editors
Sauce Labs - https://saucelabs.com/
Browser Stack - https://www.browserstack.com/
MailGun - http://www.mailgun.com , http://www.mailgun.com/google
SendGrid - https://sendgrid.com
MailChimp - https://mailchimp.com
Mandrill - http://www.mandrill.com/
AWS SES - https://aws.amazon.com/ses/
Mail Trap (for testing only) - https://mailtrap.io/
Headway - https://headwayapp.co/
Google Analytics - https://analytics.google.com
Heatly - https://www.heatlyanalytics.com
New Relic https://newrelic.com/
Inspectlet http://www.inspectlet.com/plans
Zoom Analytics http://zoomanalytics.co/
LiveSession - https://livesession.io/
Microsoft OneNote - https://www.onenote.com/
Evernote - https://evernote.com/
Google Keep - https://keep.google.com/
Pocket - https://getpocket.com
Asana - https://asana.com/
Basecamp - https://basecamp.com/
Trello - https://trello.com/
Airtable - https://airtable.com/
Meister Task - https://meistertask.com
LeanKit - https://www.leankit.com/
Pivotal Tracker - https://www.pivotaltracker.com
Wrike - https://www.wrike.com/
Wunderlist - https://www.wunderlist.com/ (Replaced by Microsoft Todo)
Microsoft Todo - https://todo.microsoft.com (Replacing Wunderlist)
Todoist - https://todoist.com/
I Done This https://idonethis.com/
Taskade - https://www.taskade.com/
Nozbe - https://nozbe.com/
Toggl - https://toggl.com/
PrimaERP - https://primaerp.com
ClockIt - https://clockit.io/
Zoho People - https://www.zoho.com/people
Bitrix24 HR System - https://www.bitrix24.com/uses/free-hr-system.php
Pomodoro Technique - https://en.wikipedia.org/wiki/Pomodoro_Technique
WordPress - https://www.wordpress.org
Drupal - https://www.drupal.com
Joomla - https://www.joomla.org
WooCommerce for WordPress - https://www.woocommerce.com
Magento - https://www.magento.com
OpenCart - https://www.opencart.com
Prestashop - https://www.prestashop.com
Shopify - https://www.shopify.com
Wave Apps - https://www.waveapps.com
HubSpot CRM - https://www.hubspot.com/products/crm
Insightly - https://www.insightly.com
ZohoCRM - https://www.zoho.com/crm/
Slack - https://slack.com/
Microsoft Teams - https://teams.microsoft.com/
Mattermost - https://mattermost.com/
Rocker.Chat - https://rocket.chat/
Zendesk Chat (formerly Zopim) - https://www.zopim.com/
Olark - https://www.olark.com/
Facebook Messenger - https://web.facebook.com/business/products/messenger-for-business
WhatsApp - https://www.whatsapp.com/
Facebook - http://facebook.com
Twitter - http://twitter.com
LinkedIn - http://linkedin.com
Google+ - http://plus.google.com
Instagram - http://instagram.com
Pinterest - https://www.pinterest.com/
YouTube - http://youtube.com
HubSpot - https://www.hubspot.com/
Marketing: https://www.hubspot.com/products/marketing
Sales: https://www.hubspot.com/products/sales
Website Grader by HubSpot http://grader.com
Buffer App - https://buffer.com
HootSuite - https://hootsuite.com
TweetDeck - https://tweetdeck.twitter.com
CrowdFire - https://www.crowdfireapp.com
QuickTwit - https://quicktwit.com
Uber Keyword Suggest - http://ubersuggest.org/
Social Media - http://locowise.com/
Visual Website Optimizer - https://visualwebsiteoptimizer.com/
Tweriod - http://www.tweriod.com/
My Site Auditor - http://mysiteauditor.com
Upcity free tools - http://upcity.com/free-tools/seo-report-card
Free traffic increase - http://www.10khits.com/
WooBox http://woobox.com/
Add Shoppers - http://addshoppers.com
BuzzSumo - http://buzzsumo.com/
Static html app - https://statichtmlapp.com/
Hashtagify - http://hashtagify.me/
Ritetag - http://ritetag.com/
Tagboard - https://tagboard.com/
Twitalyzer - http://twitalyzer.com/5/index.asp
Trendsmap - http://trendsmap.com/
Shortstack - http://www.shortstack.com
Post Planner - http://www.postplanner.com/
Biteable - https://biteable.com
Powtoon - https://www.powtoon.com
Animoto - http://animoto.com/
Openshot - https://www.openshot.org
Pexels - https://www.pexels.com/
Shopify Burst - https://burst.shopify.com/
Unsplash - https://unsplash.com
Place Image (Stock photos generator) - http://placeimg.com/
Shopify Logo Maker - https://www.shopify.com/tools/logo-maker
Logo Joy - https://logojoy.com
Logaster - https://www.logaster.com/
Cool Text - http://cooltext.com/
Online Logo Maker 24 - http://onlinelogomaker24.com
Free Logo Services - http://freelogoservices.com
Graphic Springs - http://graphicsprings.com
Design Mantic - http://designmantic.com
Zillion Designs - http://zilliondesigns.com
Logo Maker - http://logomaker.com
Pagemodo http://www.pagemodo.com
Canva - https://www.canva.com
Snappa - https://snappa.com
Photoshop - http://www.adobe.com/products/photoshop.html
Photoshop Express - http://www.photoshop.com/tools
Pixlr - https://pixlr.com/
Microsoft Expression Design - https://www.microsoft.com/en-pk/download/details.aspx?id=36180
Fotor - http://www.fotor.com/
Create GIF - http://gifbrewery.com/
Stamp creator - http://www.speedystamps.co.uk/
Method Draw (SVG Editor) - http://editor.method.ac
AConvert (Image to SVG Converter) - https://www.aconvert.com/image/png-to-svg/